Hi all,
I decided to share, for those interested, my experience with WP7. As background: I am a programmer, I have developed for iOS, and I am a Linux, Mac and Windows user in a regular basis. I used an iPhone since the original version, and have used iPhones, Androids and, for the last year and a half, a WP7 (I have the feared Samsung Omnia 7). I work at an university and I am not related to M$ or Nokia or any other phone company in any way.
I would like to start with the positives: Windows Phone is a very fresh operating system. It is visually extremely attractive, fluid and comfortable to use. In terms of the design, it focuses in the information, giving text a central place when text is the focus (of course, images and videos when they are the focus). It succeeds in this most of the time. In addition, they data aggregation is the best of any platform (ok, maybe WebOS was better, but I have no experience there; ... and RIM X is not out yet). If you have contacts from multiple sources (Google, Windows Live, Facebook) you can aggregate them in the people hub, and link multiple accounts to the same person. Then you can also group the individuals and create feeds of this group, if that is your liking. Calendars are aggregated in a similar way into the Calendar Hub. This might not be appealing to most /. users (Facebook!? ugh!) but regular users do like it. The cloud usage is also excellent: most data is also available online from the M$ servers over a Live account (yeah, well.. that is a two edge sword), and they even include remote phone lock and wiping (which is a nice touch). The browser, IE, is actually quite good (hey, I was surprised too...), so are the email and calendar apps. The maps improved a lot with WP7.5, and the directions are EXCELLENT, I find them much more accurate than the ones I get in the iPhone (and those were quite good already). Voice recognition? if you use it (I don't), they had it before the iPhone. The lock screen is full of useful information, which I like, and the tiles provide a great overview of an app without opening it. The tiles home screen looks deceptively simple, but it can pack quite some information in one screen with the tile animations. The Office Mobile client is nice, including the One Note Mobile; all synchronize to the M$ cloud. The keyboard is one of the best I have used, and the support for multiple languages is fantastic (Android is very close here too when using additional keyboards). The Music player is surprisingly good. And if you are a developer, you will love the Touch Develop app from M$ that allows you to write scripts visually and explore the API of the OS.
Now to the not so nice things.. (and I have quite a list). The first one is this thing with text overflowing the screen to the right.. it a design decision that I cannot understand, but I have learnt to live with it (still don't like it). The aggregation sources are at the moment locked to what M$ offers: i.e. you cannot are your own sources. This means no CardDAV, no CalDAV, no LDAP.. which sucks for enterprise environments. You are also out of luck with VPNs, because they are not supported yet (sigh....). The email app is OK for normal users, but if you use folders heavily, or have thousands of emails in your inbox, it is not the best app (also, it only supports server-side search in M$ and Google accounts). Battery life is short (but is that the fault of the OS exclusively?), I have to carry 2 batteries when I am on the road. And then there is the lack of apps: it is improving, but it is nowhere near the level of the apps in iOS or Android. And finally... programming in WP7 can be really difficult, which I think is the biggest drawback.
For short, the platform is still not fully mature, and it is clearly a platform for everyday users. It covers the needs of a user that wants to stay in contact with his friends, uses Facebook, Xbox live, play games, checks email, tweets something, finds some directions in the map, etc. Power users and enterprise users will find the platform still lacks key functions like VPNs and Calendar servers (heck, it only supports multiple calendars in Live accounts, even Exchange servers are limited to one calendar). But I find it to be the most polished interface of all: it makes good use of visual elements, it focus in the information (displaying, consuming, sharing), and gets the job done.
So, from this point of view, I believe the next release of WP7 is going to be critical for its survival. The OS is great for everyday users. If it addresses the key issues to appeal to the wider audience of business folks, it will become a hit. In my opinion, M$ has to embrace openness in the platform, giving more choices in the software side, and providing a better development experience.