It's a great device if you don't really care much about using custom ROMs etc. Currently no AOSP ROMs has a working camera and are forced to use the stacks from the Z1, creating the famous fish-eye bug. Hopefully Sony fixes the issue in their unified 3.10 kernel.
If you don't care about all that, and simply need the phone as is, it's perfect. No issues whatsoever, super smooth and amazing battery life.