1 - Sometimes the touch screen isn't very responsive. I have more non-responsive hits with this phone than I've had with any other phone prior.
2 - Despite having a huge battery, the battery life on this thing sucks! I have it in power saving mode and always have all apps closed out, location and bluetooth off, and screen brightness way down. It still performs poorly in comparison to the lg g2 and galaxy s4 that I've used most recently.
3 - Something with the design of the phone weakens my signal considerably. All the places where I would get full bars with my Galaxy, I now get 2 or 3. The antenna placement in this thing seems to be really terrible.
Like I said, I'm still pleased with the phone overall, but some definite improvements will be required to keep me around for the one plus two.