I have had the phone since release (pre-ordered, picked up on Thanksgiving Eve) and while I love the phone I do have gripes with it (more with W10M, but some with the phone). For starters the phone heats up a LOT more than they advertised with the "dual-liquid cooling" system. If I play any game (graphically intensive or otherwise) for more than about 10 minutes, the bottom half of the phone (opposite end of the camera) gets quite warm. It's not intolerable as it's a plastic backing rather than metal but its a bit uncomfortable. Secondly the phone does have creeky corners. I know this can be fixed with one of the mozo cases, but I have not been able to get one yet (I want the white leather and cannot seem to get it anywhere yet). These are my only real gripes with the phone itself which is why I still love it.
Now my issues with W10M, randomly apps that have worked great will just stop working or start bugging out (with no updates to the UI or the app). Take for instance, Netflix only works about 40% of the time for me since moving on from 8.1. It either won't even open or will not load a video/randomly close. It's very frustrating when it takes over an hour to watch a single 30 minute sitcom. Next the eye scanner is super inefficient. I have followed the advice of others and focused it in different lighting to try and hone it but I can still usually type in my pin before it finds me every time. My email issue I previously had was fixed so that is no longer a problem but it was still a major problem for me when it was present. My final issue....Loading....It's not super often but I have been getting the "Loading..." screen when trying to go back to Start on some occasions. It's always coming off of something different and never has it occurred from the same thing twice.
Like I said though, I do love the phone and WM, but it is not everything I hoped for. I will be happy with this phone until next year at least. If the Surface phone happens and releases...I will be getting rid of this immediately!