Xperia Z1s VS ??? -- Need opinions

I'm shopping for a new phone, and looking to ditch AT&T for T-Mobile. T-Mobile is going to pay my early cancellation fee and give me how ever much they deem worthy for my GS3. I really like the look and build of the Z1s, plus it comes with a BT speaker.

Is there anything I should look at otherwise? I was thinking about the Nexus 5 and the Moto X, but I've played with them and they were just kind of "meh" to me. Also, I don't want a giant phone like the Z Ultra.

Any ideas, guys?