Let's just get it out of the way: Windows Phone 7 is the most exciting thing to happen to phones in a long time.
There's a million reasons why Windows Phone 7 matters. It's the most important PC company in the world, battered, bruised and badly lagging, coming back to the next generation of PCs, after crashing on a bunch of rocks and abandoning ship. It's potentially the most tectonic shift in mobile since the launch of iPhone and Android over three years ago. It's Microsoft starting over and betting massively on its future. It's a very different kind of Microsoft product. It could be the beginning of something truly great.
I've been using Windows Phone 7 off and on since a preview build in July, when I detailed as much of Windows Phone as possible in excruciating detail (so that's where you should go for the deep explanations). Most of that still holds up.
Windows Phone 7 is the most aggressively different, fresh approach to a phone interface since the iPhone. Everything is super flat and two dimensional. Ultra-basic squares, primary colours and lists. Fonts are gigantic and clean, white text on an almost universally black void. It's fluid. The spartan nature is emblematic of the entire OS, for better and for worse. You don't get a lot of choices. There are no custom ringtones, for instance. It just is how it is. And while it looks and feels very different in some regards, it's uncanny just how inspired Windows Phone is by the iPhone in its underpinnings, versus anything else Microsoft has ever made.
The interface is oriented around three core concepts. There are Hubs, which are essentially panoramic apps that span multiple screens. Ironically, what really proves the Hub concept works are the third-party apps that use it. It works perfectly with Twitter, Foursquare and Facebook, swiping over a screen to get to mentions, or to see your friends' check-ins. Live Tiles, the home screen's icons, update themselves with fresh info, like email counts, though they don't go far enough to replace bona fide widgets. And the app bar is semi-persistent menu/taskbar in apps hiding actions, like to start a new email or switch tabs in Internet Explorer - a necessarily evil, given how radically Microsoft has reduced the onscreen UI.
The core OS is very good, if embryonic in some ways, much like the original iPhone. It's really up to the apps to make Windows Phone usable. Microsoft won't have 250,000 at launch, but true to their word, it seems like they'll have a lot of what's needed, with the early launch apps feeling surprisingly. (That said, it's still way too tricky to find things, especially given there ain't that much in the store yet.) It could be the best platform launch yet. Foursquare is tidy. The Twitter app is second only to iPhone. The Facebook app is phenomenal in form and function, better than the iPhone (though it makes the integrated Facebook stuff in the People seem crappier by comparison). The Xbox Live games are excellent, for the most part. Missing still from the App Marketplace and from the phone itself? A decent messaging app.
The lack of third-party multitasking itself isn't a pain, per se, but the way the phone quickly "dehydrates" third-party apps like Twitter or games once the lock screen engages is seriously detrimental to the overall smoothness of the experience, like smashing into a road bump every mile or so while cruising in Ferrari down the autobahn. Copy and paste is coming next year, but I didn't really miss it.
Overall, you can see where Microsoft is going with things, and it's dead on, but sometimes you wish it would be there already, just like you sense what iPhone 4.0 would be like right after playing with an iPhone for the first time. I want Windows Phone 8.
Windows Phone is different, and very good at the same time. Difference is something I value a bit too much, perhaps, but it's partly why we were so blown away by webOS, too. The flatness of the UI is exceptionally stylised, and some people might hate it, I dig the utter essentialism of it, at least when it doesn't get in the way of function. The design is thoughtful overall - notifications for a text message or new achievement slide over the top of the screen in non-intrusive way.
Except for the desktop side, where things like Live.com still feel sprawling and messy, it's a nearly perfect melange of Microsoft services - Bing, Zune, Xbox, Office - in a cohesive, logical and typically beautiful way. (Though the more tied into Microsoft you are, the better experience you'll have, like Google and Android.) The native apps are almost gratuitously tasty eye candy. As a location loads up in Bing Maps, a fog fades away from the map. The Outlook mail app makes email look crispy in a good way. Even IE doesn't suck, responding and loading smoothly, though anything that renders poorly in desktop IE will do so on the phone. It feels like Microsoft at its best.
Microsoft's approach deftly balances the cloud and the phone. When I turned on the first for the time, I plugged in all of my account info, and my contacts, emails and Xbox Live account all appeared instantly, the way they should. But I can also move the phone from PC to Mac and back without any problems to pull in all of the right photos and music from both machines. It's a wonderful agnosticism.
Earning Xbox Live achievements standing in line at a coffee shop is pretty baller.
Remember how iTunes wasn't so bad, and then Apple kept pinning on feature after feature, bloating it into a massive, disgusting corpus? Yeah, well, the Zune desktop client is slowly meeting the same fate, now that's it used to sync Windows Phone and as the desktop browser for the app marketplace. Zune's interface works pretty well for music and videos! Not so much as a phone and app manager. The integration feels awkward, like Microsoft was trying to figure where to stick the phone and just went "aha, Zune!" For instance, you can't actually see the apps on the phone in the Zune client. On the other hand, the radically simple Mac sync client won't even let you pull pictures off the phone. In general, the platform's weakest link is anything designed by people outside of Windows Phone - the Live site is still kinda messy and blah, for instance.
This is an active interface. You're going to be constantly swiping, flicking and manipulating it. That's because of in pursuit of the stark aesthetic, there's a radical reduction in elements on screen. Take the home screen, which only fits eight tiles at once - so to get to something else, you've gotta swipe down to your other tiles. (The iPhone gives you access to 20 items; Android 2.2, up to 19 items.) Or worse, if it's in the loooong list to the right of home, you've gotta swipe to the right, then flick down the list to get to the app you want, since there's no universal search to call up apps. It's more annoying with email, since there's no singular email app. Every email account creates its own tile, which sucks when real estate is so valuable. And then you've got situations where the text runs off the screen in lists, like "Star Wars: Battle Fo" in Xbox Live.
The app marketplace organisation and app discoverability could use some work, both on the phone and on the desktop. Browsing for apps is the single most painful experience of Windows Phone. Loading app lists takes forever, and it's the one time the phone ever becomes totally non-responsive. Grabbing an app requires confirming and reconfirming like 6000 times. It just needs to be a better experience, all around.
There's still some very 1.0 tendencies that are like bad flashbacks to the original iPhone. I'm reading Twitter. I lock the phone and put it in my pocket to buy a pack of gum. A minute later, I pull it back out to read Twitter. Press unlock. I'm hit by a "Resuming...." screen. Then all the tweets have to reload. There's no multitasking in WP7, and I'm using a phone with a 1GHz processor and 512MB of RAM, but I have to sit through a de facto loading screen every time I lock and unlock the phone with an app running? Apps may dehydrate and rehydrate themselves to preserve battery life, but the user experience of that right now is jarring and crappy.
Windows Phone 7 is really great. A lot of that greatness is potential. But if anybody can follow through on their platform it is Microsoft. Should you buy this instead of an iPhone or Android phone? In six months, after the ecosystem has filled out and we get a much clearer picture of what the app scene is going to look like, the answer will be more definitive. But right now, it's definitely an option. Considering where Microsoft was just a year ago, that's saying a hell of a lot.