Moving to Explorer, there are few changes. Downloads is no longer a Library but is now instead a standard physical folder, which makes more sense. But the main navigational bits in Explorer, and the UI, are largely unchanged since M3 otherwise. I like the new Explorer quite a bit, though the new view style, called Content, remains an enigma. I recall when Microsoft introduced Tiles view during the XP beta and wonder if Content isn't destined for a similar future. That is, it was designed for something very specific (in Tiles' case, the default [My] Computer view), something that we're just not privy to yet. It doesn't seem very useful to me, unless it's just a details view for large resolution monitors.
The new Content view appears to be a Details view replacement for large resolution displays.
Libraries remain an enigma, though they're mostly unchanged since M3. I think that this feature will confuse users for years to come, but I do recognize the need to move away from physical folder locations (and drive letter for that matter) in Windows. It's an ongoing process, apparently.
Networking doesn't appear to have changed much since M3 either. The Network and Sharing Center and HomeGroup configuration pages are seemingly identical, suggesting that these features were in place and baked months ago.
Networking hasn't changed much since earlier builds.
Moving to the built-in applications, we're looking at a pretty sparse collection now. As everyone must know by now, several previously key Windows applications, like Windows Mail, Messenger, Movie Maker, and Photo Gallery, are no longer included in Windows 7 and are instead made available as free downloads via Windows Live Essentials. (Other Windows applications, like Windows Calendar and Contacts, are also gone in Windows 7 are replaced by functionality in Windows Live Mail.) That's fine, I guess, but it creates a weird situation in which Windows 7 has a DVD making application (Windows DVD Maker) but no way to manage or edit photos or videos. Huh?
Windows Media Player is mostly improved over its predecessors, but you no longer configure "watch folders" from within the application (nor can you manually search for new content via the familiar F3 keyboard shortcut). Instead, Microsoft expects users to manage this type of thing via Libraries. This didn't work properly in previous builds, but in the beta, when I add specific folders of music to my Music Library, for example, that music is picked up by Media Player and organized accordingly. (HomeGroup integration also lets you play back content from other PCs on the network.) I haven't been able to test the Play To feature yet; this will eventually let WMP control play back of media to smart connected devices, which sounds interesting.
Windows Media Player now correctly picks up content configured in your media-oriented Libraries.
Media Center got mildly updated in the post-M3 builds but hasn't changed since. There's a nice new Get Started experience that helps you get up and running quickly. WordPad and Paint haven't changed from what I can see.
Windows Media Center isn't evolving as quickly as I'd like, but it does make it easier for users to get up and running now.
The new Windows Media Center Now Playing view resembles the Zune PC software.
Internet Explorer 8 gets some huge compatibility improvements in the Beta build and picks up the Compatibility List feature that Microsoft plans to ship separately to XP, Vista, and Windows Server users via an IE 8 RC sometime soon. While improvements to Web rendering are welcome and needed, IE 8 still renders some pages incorrectly in this version (I'm looking at you, Gmail), but hopefully Web site owners will get serious about getting ready for the next IE and correct these issues.
Internet Explorer 8 offers better compatibility with Web sites written for older browsers. (It works fine with the SuperSite, of course.)
I'm eager to test the Device Stage stuff we saw at PDC, but there are still no Device Stage-compatible devices I'm aware of, and I haven't found a way to trigger this intriguing new UI in the Beta build. Update: I do, in fact, have a Device Stage-compatible device: The Sansa Clip. Thanks to Andrew for the tip, and here's a shot:
Devices Stage is like an Activity Center for a particular device.
While legacy UIs like Device Manager are still present, there's a new control panel UI called Devices and Printers that seems destined to finally replace Device Manager. You can launch Windows 7's vaunted Troubleshooters from this UI, in fact, which is useful for finding and fixing hardware problems. It's only a million times nicer (and easier) than Device Manager, and I'm assuming that was exactly the point.
Devices and Printers allows you to easily run troubleshooters for misbehaving hardware.
At this point in time, Windows 7 is an enigma. Many are excited about testing this next version of Windows, and I'm sure millions of people will do just that when Microsoft makes the Beta available publicly in January. But in use, Windows 7 is fairly unexceptional in the sense that, yes, it has some nice improvements over Windows Vista, but, no, none of them are particularly major changes. In this sense, Windows 7 is much like your typical Microsoft Office release, a nicely tweaked version of the previous release. (Cue the obvious Steven Sinofsky anecdote here, I guess.) That said, Windows Vista is clearly in need of a spit-shine, not to mention a public execution, and Windows 7 will provide Microsoft with a way to do both.
The obvious question here is, should you even be running the Windows 7 Beta on production hardware? If you're a regular reader of this site, I suppose the answer is yes. I've not run into any insurmountable issues with the Windows 7 Beta on the three systems to which I've installed it so far, and it's proven quite compatible with all of my hardware and software. That said, you're mileage may vary, so approach any install of this Beta with caution, and be sure to back up all of your important data ahead of time. I have not upgraded any Windows Vista PCs to the Beta yet, but will do so in the future. For now, I have no advice about upgrading, sorry.
Performance-wise, Windows 7 appears to be in the Windows Vista ballpark. It certainly boots up more quickly than its predecessor, and it is a spirited and lively system in use, with one familiar exception: File copies, especially network-based file copies, are still often surprisingly slow. I have a feeling Microsoft still hasn't fixed what appears to be an endemic issue with the Vista-era networking stack.
I'll continue using the Windows 7 Beta on all of my day-to-day PCs going forward of course and expect to have more to say about this release in the weeks and months ahead. For now, I applaud Microsoft for shipping such a stable and usable beta release. I just wish there was still time to rethink or at least discuss changes like the enhanced taskbar and Libraries, both of which I expect to confuse users.
The Windows 7 Beta is recommended, but only for technical users.