Nexus 6 comes with encryption enabled and no way to turn it off. This makes the device run slower.
Also, the only real negative from the reviews is the dim screen.
Battery reports are all over the place from worse than the N5 to multiple reports of a day and half, which makes me think it had to do with two known bugs in pre-final Lollipop: the WiFi drain and miscellaneous battery drain. Both of those were present on the N5 preview and whenever I got them it would wreck my battery life. So, it is very possible that one or both were in the pre-final N6 software. We know for a fact that reviewers got, at least, two OTA's during their review process.
And the camera, that's 100% software. The sensor in the N6 is excellent, but the stock camera app doesnt even take advantage of the new APIs. Either Google will fix it or 3rd party apps will.
Facts? gtfo of here with those