So, I haven't really talked about the preview in quite a while. However, I have fully updated to the latest version (10041) and can give a nice little tour.
First off, the system theme has been updated. The taskbar now uses a flat theme with a thin bar underlining the icons of programs that are open with the focused program having a highlighted box rather than recycling the modified 7 theme that was used for 8. The narrow 'show desktop' button on the far right of the taskbar from 7 has also been restored.
Another handy feature in this version is that any file can be pinned to the taskbar by simply right-clicking on it and selecting 'Pin to taskbar' (which I did with the recycle bin, and then hid it on the desktop through the usual method) and any file or folder can be pinned to the Start Menu the same way.
The Task View button on the taskbar displays all open windows in a spread, allowing you to pick the one you want. Handy if you have multiple instances of the same program, otherwise you might as well just use the taskbar.
Task View also has a virtual desktop function where you can assign windows to different desktops for organizational purposes. Just open Task View and click the 'New Desktop' button. Once you have more than one, you can simply drag and drop your windows to the desktop you want via Task View. Eventually, icons on the taskbar will supposedly limit themselves to only showing the programs open on that desktop, but that isn't currently implemented.
The Start Menu, now just called Start, has been redesigned again. The size is now fixed; you can't drag and drop the upper edge like before and it doesn't expand or shrink horizontally with your tiles either. However, there are now re-nameable headers available for organization and you can scroll through the tiles vertically if you have enough for them to continue below the bottom edge. The search menu has been embedded in the taskbar instead of the Start Menu, though invoking Start, either by clicking on the button or tapping the Windows key, will still automatically drop an I-beam in the search field allowing you to quickly search for programs like in 7. It's also slightly transparent, but that's not overly relevant.
Start also has a button in the top right to maximize the menu like a window. This primarily seems to create more room for tiles, but I suppose that the 'Most used' section may expand, too. Windows remembers which mode you last had Start in so you don't need to keep maximizing or un-maximizing it all the time. It's also more transparent than the small version, but that also is not overly relevant.
If you don't like Task View or Search being on the taskbar, you can easily disable them by right-clicking on the taskbar and turning them off. You can also condense Search down to a single icon instead of the input box. The Search icon changes from a magnifying glass to the Cortana logo depending on if you have Cortana enabled or not. If you disable Search or shrink it down to just the icon, the box is still accessible by clicking on it or opening Start.
Cortana is currently included and you can invoke her by clicking in the search box, clicking on the Cortana logo, or saying, "Hey, Cortana," into a microphone. Currently, the Win10 version of Cortana doesn't have as many features as the Windows Phone version, but it does display news and the five day forecast. I don't have a microphone so I can't check the extent of the features, though. You do need a Microsoft Account to use Cortana so you may want to watch what you tell say into the mike or type into the box depending on exactly how much data it can pull. If you don't have a Microsoft Account, then Cortana is disabled and Search replaces it. You can also easily disable Cortana through the menu in the upper left.
Cortana
is voiced by Jen Taylor and
does pronounce names correctly, and can be corrected if she doesn't. If you really want, there's nothing stopping you from having Cortana refer to you as Master Chief, Chief, or John-117. Or Sexy. Whatever floats your boat.
As far as the bundled apps go, it's a bit of a mixed bag, though the beta status probably doesn't help. Many of them have a new button added to the usual minimize, maximize/un-maximize, and close buttons that functions as a full-screen toggle. When these programs are in full-screen mode, you can bring up the titlebar to go back to normal size by simply moving your mouse to the top of the screen and waiting about a quarter second. The old menu bar with things like file, edit, etc. is gone in favor of a drop down menu on the far left side of the title bar that uses a simple 'three horizontal lines' icon.
The Music app is a huge improvement over using Media Player for music. It automatically scans your Music library (same thing as the Win7 user libraries) for songs. Creating, editing, and deleting playlists is very simple. At the main Collection screen, you can sort your music by album, artist, or title. The Explore screen is a music store, but I haven't tried it at all. There's also a Radio screen, but it looks like that requires some kind of paid account. There is a trial mode if you really want to check out the Radio function.
The Video app is similar. There is a store, divided into movies and TV, and a Collection screen which searches your Video library. The store selection looks pretty good, and I found a couple episodes free, but I can't get them to download. On the bright side, it has support for MKV format videos and local video playback is definitely improved over what Media Player offered. If you're a VLC fan this probably won't change your mind, but it's definitely better that what came before.
I haven't really tested older games much for backwards compatibility, but FO works just fine, as does Gimp and VLC. Installation of all three went perfectly. 10 is also compatible with the Vista, 7, 8, and 8.1 drivers so there's no need to worry there.
Ye olde Widows Explorer has been renamed File Explorer and now defaults to a new Quick Access area displaying frequent folders and recent files instead of the Libraries area. Libraries is still available from the side pane, but it's not the default folder anymore. There's a whole bunch of new icons, too. It also uses a ribbon instead of a menu bar.
Computer/My Computer has been renamed to This PC and slightly reworked. It now displays the current user's folders in addition to the drives.
Control Panel is being phased out in favor of the Settings window. If you still want the Control Panel, it is still available by right-clicking on the Start button, along with a slew of other system management features.
The old network menus have been replaced, mostly to fit in with the new theme more. It seems to have all the old options but I haven't done a comprehensive check.
The new Notification Center, located between the clock and the systray, lists all notifications you have received recently so if you miss one of those little corner-of-the-screen pop-up notices you can still find them. And apparently I've run out of attachments so no more pictures.
10 is certainly different, but whether it's better than 7 or not I think largely depends on how you like the UI and how good the backwards compatibility is. It runs FO, so that's a good sign, but I haven't done more in-depth testing. If you're using 8 on a desktop or laptop, by all means, get 10 as soon as it's available, but if you're on 7, then the biggest reasons to upgrade will probably be the free upgrades to future versions and DirectX12.