Summary: I think is the best phone I ever had. Paid too much on that time but it endured me for 2+ years which I thought it would be old and obsolete by then but it is still way better than many mobiles still today. Changed it for the Xperia Pro. Had its pros and cons.
Summary: The X1, is a great phone. However, compared to other phones now a days it tends to lag a bit. That could be because I flashed a new rom to it which uses higher cpu frequencies, or because I am always running android instead of the intended WinMo 6.1.
Summary: I have been using this phone on the last couple of days with Costa Rica Kolbi's 3G network and it works great. Calls are of good quality so as the internet speed. Windows Mobile is a little bit slow to stat but otherwise performs well with different applications.
Summary: This is the only cell phone I ever bought that just worked right out of the box without a thousand questions. It connedted to the web, found new panals, downloaded my mp3 files and assorted and assembled all my music and video files. It is like haveing a real computer in the cell phone.
Summary: Definitely Sony Ericsson did it right. The Xperia X1 is not only a very good mobile phone but also a great windows based portable device. Maybe the only improvement I would request is it's battery performance specially if you are a Wi-Fi or internet applications fan.