Some additional random notes:
1) I found I could bring the screen brightness up to acceptable levels while using auto brightness by moving the slider all the way to the right...it's got one of those nifty adjustable auto brightness features.
2) battery life appears good so far. Used it all day in NYC, no problems.
3) I'm not thrilled with the sound quality. it's ok for android, but not great compared to windows phone and iOS. I compared the same track using the Z1s,an HTC DNA, an iPhone 5, and a Lumia 928. Out of the box, the Z1s sound is very tinny and flat. turning on crystal audio helps a bit, and fiddling with the equalizer definitely improved things to be a little better than the DNA (which is clear but has too much bass...thanks beats audio!). Both iPhone and Windows Phone had a much fuller sound. Not a deal breaker but if you're an audiophile you may want to try things out yourself.
4) Flash photography is really excellent. Sony has really nailed the white balance...well exposed indoor pictures, no yellowing in the backgrounds, no overexposed faces in the foreground. Very impressive, and a nice change from my Lumia 928, which despite the xenon flash takes craptastic flash pictures. Pictures in low light with no flash are also good, but here the noise reduction is too aggressive, making the photo look airbrushed compared to the 928 and iPhone.
5) Call quality is good, even over wifi calling. Miles and miles ahead of my old HTC One S. Reception appears good for TMO, the usual caveats about indoors apply. To TMO's credit, I did drive while on the phone from midtown to suburban NJ through the Lincoln tunnel without dropping the call. Almost lost it at the turnpike toll booth but TMO must have some very good software on the back end to keep the call going through a rough patch.
6) Small stuff: Total lint magnet. phone is constantly covered in cat fur. the usb cover is less fiddly than I expected. Not usually a fan but seems to be a good compromise here.
7) Bloatware: yes there is a lot of sony software here. However, it seems quite good, and a nice addition to the phone. More along the lines of the Nokia exclusives for Lumias. the TMO software is out in full force but what are you going to do...