Hello there and welcome to the Forum!
I am testing out an X8 for the Sony Ericsson Talk forum and I have been pretty impressed so far. I would have to ask what you want the phone for because then that would give members more of an idea when giving pro's and con's.
I use the phone quite happily for texting, few emails, facebook / twitter and even occasionally the odd phone call!
I also have an X10 and there isn't much that the X8 can't equal it on once I installed the same launcher and most of the apps also work on it as well.
The camera isn't quite as good, but daylight shots are pretty good. There is no zoom on it but again not a big deal. The audio quality (to my untrained ears) is pretty good and the screen and sound beat my X10 and hubby's iPhone when watching a YouTube video.
I will leave it there and let others chips in.