As an Xperia X1 owner, I've had it since January and have been incredibly frustrated by it for an entire year. In fact I am so upset about it, I have vowed on my mother's life that I will NEVER buy anything the Sony group sells again. So, allow me to offer my rather maverick $0.02.
I chose the X1 because it's got a HARDWARE keyboard, because everyone says hardware is a lot easier to use than virtual. Wrong. It takes more effort to press, and after 2-3 months the X1's specific keyboard started to develop issues (see the XDA forum for details). It started typpiinngg like tthis att randoom with no discernable pattern, repair comes back saying the unit's problem-free and they wouldn't do anything for me. Looks like the only solution may be to take it apart and thoroughly clean the enclosure, which I don't have the know-how to conduct.
You know what, now that you're used to the general dimensions of the keyboard on an X1, the landscape virtual keyboard on the iphone will be a snap. A lot of people have issues with a virtual keyboard mainly because they're not used to the feeling of not pressing down on something solid, but I have had no issues with that, and I seriously regret considering this piece of popular opinion in making my decision. I have more than a passing experience with keyboards like the E71's and older BBs, and while they might be more durable than the X1's, the iphone is still ace for me when it comes to keyboard on a phone.
The Windows Mobile debate aside, the X1 was shipped with terrible factory ROM for the longest time. It would crash, and then crash again during boot upon soft reset. The Panels manager would freeze it. Click one thing and you might have to wait and wait and not know if what you do has been registered. I have flashed many, many custom ROMs, and while they have improved things somewhat, 1) they're rarely ever the full solution fanbois make them out to be, as much as I hate to be unthankful, there's always something wrong; and 2) I paid close to $900 at launch for a phone I have to slave away on like this, essentially learn to hack to make it even remotely usable. I now have a custom ROM that's working spiffy, but it just started drawing huge amounts of power for no reason two days ago. People like to tell me there must be a reason for it, and thus I am a hysterical ethnic woman just babbling on about nothing, but *should* I be busy troubleshooting my phone? Really?
I love to follow news and discussion on gadgets, but based on my experience this year, I think a lot of discussion are missing the boat (I paid dearly), and personally I will not buy an Android phone yet because I think the institutions and systems around it are as flawed as the ones that offer and propel Windows Mobile as a product. At the moment it's hard to see how or why Android phones should be better.
P.S. in case you're wondering why I can't rid myself of this particular phone: We just happen to not have first-world return policies in this country. Resale value of the X1 has been extremely poor locally. It was down to 50% off when mine hit the age of 2 months, and basically worthless afterwards. Eat that :P