Following the lead of Windows, PC makers have been adding multi-touch and converting form factors to their hardware lineups over the past few years, and it's been interesting watching these designs mature and evolve. But if I were to pick just one design that's stood the test of time, it would have to be Lenovo's innovative Yoga PCs, the newest of which, the Yoga 2, is available in 11- and 13-inch variants. I'll be reviewing both soon.

Well, hopefully. If you've been waiting on my Yoga 2 Pro and Dell Venue 11 Pro reviews, you know these things sometimes take longer than hoped for. (My Yoga 2 Pro review should be available this week, after a final business trip. I like to use these things in the real world before forming an opinion.)

For now, I've got two Yoga 2 convertible laptops here, an 11-inch version and a 13-inch version. This is unusual, and I'm looking forward to comparing and contrasting, both with each other and with their big brother Yoga 2 Pro. And while I will do that, we can at least compare them from a specs and initial impressions perspective now.

(You can read my Review: Lenovo IdeaPad YOGA 13 for the complete rundown of the first-generation Yoga.)

Form factor/design. The Yoga 2 11, Yoga 2 13 and Yoga 2 Pro are all, as noted, convertible laptops, or what the industry now likes to call "2-in-1" designs because they can transform between tablet and traditional laptop forms. As I noted in my Lenovo Yoga 2 Pro First Impressions and Photos article, however, this classification is an understatement for these machines as they can in fact be used in four modes: Standard laptop mode, stand mode (in which the keyboard is under the device and the screen is positioned for movie playback or a presentation), tent mode (in which the keyboard and screen are both on the outside with the body of the device formed into an upside-down "v"), and tablet mode. Lenovo pioneered this design with the original Yoga (which was itself originally going to be called the Yoga Flip) over two years ago.

Yoga 2 11

Materials. So the Yoga 2s all share the same basic design, that's no surprise. What's interesting in using them side-by-side is how noticeable the different materials used in their respective designs are. Where the Yoga 2 Pro uses a wonderful, grippy material on all exterior surfaces—including the wrist rest—the lower-end Yoga 2s opt for more pedestrian and smooth plastics. But each includes a rubberized rim, so that when the devices are used in tent mode, they stick nicely to a table or other surface.

Yoga 2 13

Size/weight. The Yoga 2 13 and Yoga 2 Pro are not as close from a size and weight perspective as you might expect, thanks to some materials and internals differences. The Yoga 2 13 review unit (which includes a hybrid hard drive; see below) weighs 3.65 pounds and is .68 inches thick. But the more expensive Yoga 2 Pro is lighter and thinner, at 3 pounds and about .6 inches thick. And the smaller Yoga 2 11 weighs 3.2 pounds and is .67 inches thick.

Processor. This one is interesting. The low-end Yoga 2 11 can be had with a Pentium or Celeron processor; the review unit holds a quad core 2.16 GHz Pentium N3520 part. The Yoga 2 13 provides more mainstream Core processors, up to an i7; the review until includes a 2.3 GHz Core i5-4200U, which is pretty much the middle of the pack these days. The Yoga 2 Pro, shocker, contains a 2.4 GHz Core i7-4500U. I suspect even the Pentium in the 11-incher will prove more satisfactory than an Atom chipset. But it doesn't help the Yoga 2 11 get Ultrabook branding: You need a Core processor for that.

RAM. Each of the Yoga 2s comes with 4 GB of RAM, while the Yoga 2 Pro steps up with a full 8 GB of RAM. But you can outfit a Yoga 2 13 with 8 GB of RAM if you wish.

Storage. Here, things get very interesting. You can configure a Yoga 2 11 with a 500 GB hard drive, which is what the review unit offers, or a hybrid hard drive (500 GB) with a 16 GB SSD. The Yoga 2 13 review unit includes that hybrid hard drive, and that should make for some interesting performance comparisons. (You could also opt for 256 GB of SSD storage or a slightly different 500 GB/8 GB hybrid hard drive.) The Yoga 2 Pro I'm reviewing comes with the 256 GB SSD.

Screen. This is of course the other major area of interest. The Yoga 2 11 ships with a 1366 x 768 IPS display, which some may find pedestrian in this age of "retina" class displays. But I think this display looks great and would work quite well for a long time to come. The Yoga 2 13 ships with a 1920 x 1080 (Full HD, or 1080p) IPS display, though there are lower-resolution offerings available too. Here, we get into the weirdness of desktop display scaling (its set to 150 percent by default), though probably not to the weird extremes we see with the Yoga 2 Pro's retina-busting 3200 x 1800 IPS display. As I noted in my ThinkPad X1 Carbon review, these crazy high-resolution screens are largely wasted on Windows 8.x, and I think a 1600 x 900 resolution would be just fine for a 13-inch display. But 1920 x 1080 is perhaps a nice middle ground between average and insane.

Yoga 2 13

Multi-touch. Regardless of resolution or size, the screen on each of these devices sports 10-point multi-touch capabilities and what's reported as "full Windows Touch support."

Keyboard. As you might expect, the keyboards on the Yoga 2 13 and Yoga 2 Pro are identical, and backlit. But I actually like the Yoga 2 11 keyboard better, despite its smaller size: It is not shiny and slippery like the other keyboards and is instead finished in a better (for typing) matte surface. That said, the smaller Yoga 2 11 keyboard may simply be a non-starter for many. But each includes a dedicated Print Screen key, which is huge (for me, at least).

Yoga 2 11:

Yoga 2 13:

Battery. Here we are in 2014, and we're still agonizing over PC battery life while it seems that most non-Windows devices (iPads, Android tablets and so on) can go hours and hours and hours on a charge. OK, Windows is more complex, and it's bogged down in legacy technologies. But the battery life of the Yoga 2 11 (a reported 6 hours) is disappointing, while the Yoga 2 13, at 8 hours, is more acceptable. I'll discuss the Yoga 2 Pro's real world battery life in my coming review, but for now we'll just say that Lenovo reports up to 9 hours and leave it at that. You get more when you pay more, at least in this case.

Ports/expansion. All of these devices ship with the same ports: 1 USB 3.0 port, 1 USB 2.0 port, a combo audio port, micro HDMI-out, and a 2-in-1 media card (SD/MMC) reader. Each features a strangely positioned power button, which is on the edge of the device so it can be used regardless of which mode you're using it in, though I don't think this is a big deal: You use it and you get used to it. (Each also features a volume rocker on the outside edge, another nice touch.) None feature the OneLink docking port found on the ThinkPad X1 Carbon, which makes sense since these are all IdeaPad-style consumer/prosumer devices.

Windows. All of the Yoga 2s come with x64 versions of Windows 8.1 (not Pro), which means they can take full advantage of 4 GB or more of RAM and is appreciated. The Yoga 2 13 (but not the 11, curiously) came with Update 1. This is not important as all new Yogas will ship with at least Windows 8.1 and Update 1 is a free and automatic update. But it's worth noting that the Yoga 2 13 booted right into the desktop, whereas the Update 1-less Yoga 2 11 booted to the Start screen.

Power. All of the recent Lenovo devices I've gotten in for review share the same flat new power plug which, like Apple's Lightning connector, can be plugged in "upside down," which is wonderful. The Yoga 2 11 comes with a smaller brick than the other two, which, come to think of it, makes sense. But it also has a 3-prong adapter, while the other two have 2-prong adapters. That doesn't make any sense at all.

Crapware. I continue to be amazed and disappointed by the sheer amount of crapware that Lenovo bundles on its PCs. From the useless McAfee Central (a Metro app, if you can believe that) to the superfluous Yoga Chef and Yoga Photo Touch apps, this thing is bogged down with stuff that just gets in the way. The problem is that Lenovo also bundles a variety of truly useful utilities that in some ways nicely differentiate its machines from the competition. It would be hard for the average user to know what is good and what can (and should) be instantly removed.

Price. None of these Lenovos is particularly cheap, but it's worth remembering that multi-touch convertible laptops are by definition premium, and not entry-level, devices. So the Yoga 2 11 starts at $649, which is roughly a $150 to $200 premium over your basic entry-level multi-touch laptop. But you could spend as much as the $799 price of my review unit. As you move up to the 13-inch version, the price increases to a starting point of $899 and a high-end of $1169. And none of the Yoga 2 models are configurable, you just buy a particular model with whatever processor, RAM, storage and screen.

While there is absolutely a palpable range of quality as you move up from the Yoga 2 11 to the Yoga 2 13 and then to the Yoga 2 Pro, each of these machines appears to be well made and of relative high quality. But I'll know more after I've used them for a while. So I'll be checking back soon, first with that overdue Yoga 2 Pro review.