Will be posting lots more thoughts as I go, and I expect AndroidNZ editor Lokhor will be doing the same shortly, since I'm sending him his one today.
Early impressions are pretty wow for the most part.
It's still plastics but really feels and looks like quality to me, because of the rounded edges and small bezel actually feels no bigger than the SGSII in the hand, so despite the 4.65inch screen size I think most will manage fine. On the topic of the screen: Wow. It is superb. Even with the Note's 5.3inch screen I had said the pentile wasn't really noticeable in normal use, here it's even less of an issue with the higher pixel density - can only see it on the closest inspection and even then I can only appreciate it very faintly.
WiFi reception is bad, worst I've ever had in a handset - most of the time can't get reception in my bedroom (hopefully this is a software issue).
GPS seems good, although only one trip under the belt so far. No GLONASS though, which is a bit disappointing.
Benchmarks average, probably mostly because of the high resolution, but even looking at a comparable screen in the Note it suffers in comparison.
ICS is superb, finally hardware acceleration in the UI and it shows, too much to talk about there in this brief post, but it is really, really good.
Face unlock easily beaten - took a picture of myself with another phone and could unlock the Nexus. If you fail to unlock with Face unlock it goes to a backup mechanism like pattern/pin unlock, but if turn the screen off again you get another chance at Face unlock (sometimes takes a couple of goes with a picture to fake it). If only they'd forced it to the more secure methods after a failure, would make it a lot more secure.
This time around I'm reviewing for Clove and Lokhor is reviewing for AndroidNZ.net, so make sure to check out both sites for coverage, and our twitter accounts for up-to-the-minute impressions and experiences.