I've now had a Windows Phone 7 device (Samsung Focus/At&T) for 24 hours and thought I'd share some of my thoughts. Note that this is replacing my iPhone 3G.
I've been looking forward to using the new phone for a while now. Certainly, working in Bing Mobile has brought me pretty close to plenty of the excitement around the new product, but Microsoft's generous offer of a free phone pretty much sealed the deal. The first hurdle was getting the device. The AT&T store was sold out and it had to be ordered and delivered. Once in my hands I was immediately frustrated by AT&T's activation mechanics. I had to take three different paths before finally getting the thing up and running. However, that frustration quickly dissolved as I started setting up and playing with the new phone.
When using a piece of technology that takes a completely new approach to an existing problem, one has to bear in mind that things that seem initially awkward are really just reminders of how one has become trained to use the previous stuff - it is a relative measure of difference, not an absolute measure of design. The biggest difference between the Windows Phone 7 UI and the iPhone is that, from an engineering perspective, it is closer to an object oriented metaphor. The tiles that one can place on the home screen are really references to objects of a variety of types. I can place a location resulting from a local search right on the home surface for easy reference. I can place a person on the home screen for quick calling and email. Each of these differently typed objects is associated with different types of actions (one can ask for directions to a location, or for the contact information for a person). Getting this is key to getting the most out of the Windows Phone 7 experience. Personally, I think this metaphor can go even further, with a more comprehensive exposure to the various types of objects.
The first app that I loaded was OneBusAway - a must for any serious public transport commuter in the Seattle area. Initially, I was disappointed with this version of the application. I think it is going to take some time getting used to, but I'd like to see some improvements. Note that, as I mentioned earlier, this is also a reminder that my first experience with the iPhone version of this app was also confusing and it took time to figure out the sweet spot in its interactions to get what I wanted out of it.
I've played with most of the functionality offered by the phone and have really learned to enjoy the experience. The calendar is great - I much prefer it to the iPhone version from a design point of view; opening Microsoft Office documents is a very smooth experience; the Facebook integration can clearly drive more use of the social networking sites features, and I really liked the idea of linking profiles across different contexts.
However, the biggest surprise to me was the Zune functionality. This really impressed me. I found the experience of playing music on the device quite delightful and the desktop Zune product is also a very well designed and engaging system. I was also very happy with the way in which the phone integrates data with the cloud, including pictures and OneNote documents.
There is one feature that I wish existed - a simple way to transfer my contacts from the iPhone to the Windows Phone. I've read various summaries on how to do this - it is possible - but it should be far easier.