The 2014 Lenovo ThinkPad X1 Carbon is all business, and is the sleekest and most desirable Ultrabook I've ever used. Some of the design choices made on this new model are debatable, even controversial. But with the latest X1 Carbon, Lenovo has once again raised the bar on a product category that had ostensibly run out of new ideas.

Be sure to check out my Lenovo ThinkPad X1 Carbon (2014) First Impressions and Photos before reading on. Some of my hardware reviews are lagging further behind the corresponding "first impressions" articles for a simple reason: Despite a normally hectic work travel schedule, I'd been a relative homebody for the first part of 2014. But a week-long trip to San Francisco earlier this month afforded me an excellent real world excuse to put the X1 Carbon to the test. And aside from two niggling issues, it really rose to the challenge.

Let's start with the basics: The X1 Carbon is a delight to travel with. I've always espoused the virtues of traveling light, but the realities of my day job often necessitate me lugging around bags full of electronics and related cables and other gobbledygook. Not on this past trip, though. I was determined to just let go and fly with as little as possible, and the X1 Carbon—along with an LG G Pad tablet and little else—made for an incredible light carryon. Every time I slung the bag over my shoulder, I thought I had left sometime behind.

A quick look at the spec sheet confirms why this was so: At just 2.8 pounds, the X1 Carbon is light, even lighter than a MacBook Air (which has a smaller and much lower-res, and touch-less, screen). But with a 14-inch screen, the X1 Carbon is also a nice middle ground, visually and from a usability perspective, between a typical 13-inch Ultrabook (like that MacBook Air) and my usual daily use Ultrabook, the 15-inch Samsung Series 9. That device, which is now almost two years old, weighs a more portly 4 pounds and is of course bigger. It makes a difference when you have to cart it around all day.

The X1 Carbon goes and goes and goes, too. My amazingly long 6:40 flight to San Francisco ended up taking 7:50 thanks to weather issues, and I used the X1 for much of the time in the air, sans about 90 minutes for a movie (which I wanted on my tablet). Ditto for the way home, which was a less painful 5 hours in the air. When I arrived home, the X1 had 50 percent battery life left to kill. Perfect.

Lenovo rates the X1 at about 9 hours of battery life. I never saw that much battery life, but 7+ hours is absolutely in the right ballpark.

The X1 Carbon is clearly well-made, with exceptional high-end materials that look great—assuming you didn't want some kind of Day-Glo color—and feel amazing. It's a weird thing to find yourself admiring the quality of something like this as you run your hand over an edge, but that happened more than once. Granted, you do pay for this quality, the X1 Carbon is not available in anything resembling an entry-level model.

Performance never lagged, but I think I'd future-proof an X1 Carbon purchase with slightly higher-end specs by bumping up the processor (from the review unit's Intel Core i5-4300U to something in the i7 range) and the RAM (from 4 GB to 8 GB). I used the device primarily as you'd expect, for writing in Word and OneNote, browsing the web with multiple browsers, using Photoshop, and even the occasional foray into Visual Studio. No issues there.

The review unit came with a 180 GB SDD, which is an interesting middle ground before the more typical 128 GB SSDs that you see everywhere and the expensive 256 GB upgrade. I never filled up even half of that, and would be fine with 128 GB. But I really appreciated the expansion: There are two USB 3.0 ports, one of which can be used to charge a device (like smart phone) when the X1 is powered down or sleeping. And while you need to use a dongle for Ethernet, it's not USB-based so it doesn't take up one of those ports. I especially like Lenovo's flat new power port, which is unidirectional (you can plug it in upside down, so to speak) and is common between many of the firm's newer devices, including the IdeaPad Yoga Pro I'm also reviewing.

Once you get past the basics, you hit some of the more controversial aspects of the ThinkPad X1 Carbon. And it is here, I think, that prospective buyers should spend some time evaluating whether the issues I experienced will be problematic for you.

The first is the IPS screen, which is wonderful to look at if overly reflective. I'm told that this is common these days—that reflectivity, that is—but on such a work-focused machine I'd prefer to see a matte option. It supports multi-touch, which is both desirable and useful, and it certainly won't get in the way if you never intend to use it.

Reflections are a minor annoyance, however, compared to the problems one encounters with the incredibly high resolution of the display. At 2560 x 1440, the X1 Carbon screen is what we call a "high DPI" display, or what Apple would call a Retina display. This screen looks wonderful across the board: Modern mobile apps look crisp and colorful, and the text on the desktop—which is set to automatically scale to make on-screen elements reasonable to look at—is shockingly clear, almost too good to be true. Even something as simple as the text labels on File Explorer icons look amazing.

But the Windows desktop, alas, is not designed for high DPI displays. And while Windows 8.1 does of course support display scaling, not all of the applications you run support this well, or at all. So Office 2013 looks great, but when the applications need to be updated, the updater is tiny, like a postage stamp. Adobe seems particularly clueless about high DPI, and Photoshop displays toolbar icons so small you can't possibly tell which is which.

This is going to sound illogical, but over time I determined that the only way I'd be happy with the screen was if I bumped down the resolution to 1600 x 900 (and set the display scaling to 100 percent). This made everything look correctly, and there were no more scaling issues. Oddly enough, the entry-level X1 Carbon screen is 1600 x 900, and costs $150 less. But that version lacks touch.

If you're on the fence about high DPI, you need to think hard about what you really do every day in Windows, and whether that will change over time. There's sort of a knee-jerk expectation that bigger is always better, but if you're sticking to the desktop and to certain legacy applications that is not necessarily the case. At least you can bump down the X1's resolution and things still look great and retain the multi-touch capabilities that, yes, you will in fact appreciate one day if you don't now.

The second controversial area is the ThinkPad X1 Carbon's keyboard. Here, Lenovo has made substantial changes since the previous iteration of this device, and the new model sports a larger trackpad with integrated buttons (they were separate before) and, worst of all, an "adaptive function row" in lieu of real keys. There are also some questionable new key placements.

As the makers of the best portable PC keyboards on earth, I salute Lenovo's efforts and prerogative when it comes to evolving the typing experience further. But with this new X1, they may have gone too far.

The adaptive function row—a weird touch-based screen, really—does not work the way I thought it would, in that it does not actually adapt to individual applications, nor does it offer you the change to customize it for certain applications or events. Instead, what you get are four preset "modes": Home, Web Browser, Web Conference, and Function. For the most part, you can't customize these things at all, and if some functions are just missing—like Print Screen, which I use all the time—well, you're out of luck. I don't mind that this thing isn't real keys. But it's too hard wired and not customizable in any meaningful way.

I like that Lenovo includes both a trackpad and a trackpoint "nubbin" pointer on its ThinkPads, but I especially like that they let you turn off the trackpad. I did so, and was happy to see that the integrated buttons still worked just fine with the trackpoint I prefer. Most people will probably like that Lenovo made the trackpad bigger, but I don't like this kind of mouse interface, and I like it even less now that Windows 8-style gestures are built-in. I end up triggering them only by mistake.

There are some weird key placement choices here. Lenovo removed the CAPS LOCKS key, which was smart, and lets you double-tap the LEFT SHIFT key to enable this functionality (including a corresponding green light on the key plus an on-screen notification to let you know it's happened). But they also placed the HOME AND END keys in the gaping hole left by the missing CAPS LOCK key, which is weird and took some getting used to.

Some have made a case against the BACKSPACE/DELETE combo key that sits up in the upper-right corner of the keyboard, but that's exactly where those keys should be. No problem.

There is one other thing I should mention: Lenovo bundles a ton of software with this device, including some curious utilities for gesture and voice control. I didn't test any of this, and would ban much of it from my own system were I to buy this machine. But another option is to seek out a Microsoft Store and buy it there: The Signature edition Microsoft will sell you will dispense with much of the clutter.

Long story short, I think the screen resolution issue—which is not Lenovo's fault, of course—is the biggest one facing this device, and you can solve it by opting for a lower-res screen or by lowering the resolution. Personally, I find the lack of a PRINT SCREEN key to be, curiously, a huge problem, but I acknowledge most won't have an issue with this. (And the adaptive keyboard strip does have a shortcut to the Snipping Tool for those who need it.) The keyboard issues are weird but most were surmountable.

The final hurdle, possibly, is the price. The X1 Carbon is not inexpensive with a starting price north of $1200, or about $1350 and up with a multi-touch high-DPI display. Configured for my personal use, this device would cost $1800. I have never spent that much on a non-Apple portable computer. In this case, you really are paying for the quality.

Put simply, the Lenovo ThinkPad X1 Carbon is a delightful and powerful travel companion, and able to withstand the rigors of the road with ease. You will want to think carefully about the ongoing issues with Windows and high-DPI displays. And if possible I recommend checking out the X1's keyboard in person first, though I adapted to it quite quickly. But if you can afford its heady entry price, you won't find a better Ultrabook than the X1 Carbon. Highly recommended.