I've had the Z3 Compact for a couple of weeks now (from an iPhone user since 3G to 5) and it's a great phone but there's a few things potential buyers must know.
1) You absolutely need a durable case protecting it. There are multiple reports out there that a simple low drop can shatter the glass and render the phone unusable.
A guy in this thread had his phone crack spontaneously while resting on a table. (post #13). Had I known this was such an issue I may have looked away from Sony.
2) Don't plan on using it underwater. The waterproof specs are only for
fresh water. Salt or chlorinated water can and probably will damage the electronics and render the phone inoperable. It may work for a bit in a pool but you have to question why you would dunk your $500+ device into danger for a few pics. It's nice to count on the waterproofing in case you accidentally drop it in the toilet or something but don't take it snorkeling.
3) Remote Play is unusable for me. I'm right next to the system and it always disconnects after a few seconds despite the Vita working fine via direct or wifi.
Other than that I like it. The speed is excellent, images are crisp, the camera is good to great depending on the lighting.
Coming from iPhone there's a lot of little adjustments I have to make. Here's hoping that Lollipop will satisfy a lot of my issues. I'd like to do more from my lock screen like adjust volume, brightness, read email/texts and use the flashlight. I also miss being able to resume audio on the last app that was playing from the lockscreen on iphone as well as being able to keep audio playing on a video when locked.