Just got my Nexus 5X in yesterday. Liking it so far. Going to take some getting used to coming from the Nexus 4 as far as size. Some things Im not liking are the removal of the Power Control widget. I used that for my WiFi, BT, Sync, and brightness toggles. A lot faster than swiping down twice or doing a two-finger swipe down. Might just download the source code and re-build it. Was not expecting the 5 columns and 5 rows of icons, so another thing to have to get used to from having a 4x4 grid. Battery life seems ok so far. Started the day around 8:15am with 100% and am now (1:30pm) at 91% from mild usage. Overnight battery drop is great. Went to bed with 96% and woke up with 94%. The USB cable is a tad snug with the $20 Adopted case. The I ended up having to shave down the USB-C port end for the cable in my car so I could plug it in without forcing it.
The finger print touch sensor is really fast to turn the screen on and it bypasses the lock screen (I didnt realize it would do that, just thought it would wake the phone up if you have a lock screen password/gesture). Topped off at about 50Mbps on a speed test on AT&T in Clermont, FL.
When I first set up the phone, it did not give me the option to put in my Gmail account so that it would restore it. Haven't had it for a full day yet, so can post later on if anyone has questions.