tl;dr : got Nexus 4, learned iPhone 5 SIM doesn't fit in Nexus 4 and modded a SIM, learned that two-step verification for gmail is a problem when your phone isn't set up yet. Learned that, as people said, the back of a Nexus 4 is a fingerprint magnet. So far, I like the Nexus 4 though.
Gory nerdy details:
I received my Nexus 4, unboxed it, started to set it up and it wanted a SIM so I took my SIM out of my iPhone 5 and immediately discovered a problem. So I knew that an iPhone 5 used a nanoSIM and I knew the Nexus 4 uses a microSIM but I hadn't actually realized that I would actually not be able to put my iPhone 5 nanoSIM into my Nexus 4 until I looked at the problem. I ended up dicing up an old full SIM into a microSIM and then carefully cut a nanoSIM sized hole in said newly made microSIM and put it all together and then the nanoSIM shorted to the metal tray on the Nexus 4. So then I crafted a bit of tape for the edge and everything was alive...
Right up until I went to set up and it wanted me to log in to my two-step verification enabled gmail account. So then it tried to text me my verification code, but because the phone wasn't set up, I couldn't receive it. (really google? you couldn't just show it across the top?) So then I had my verification code in a phone call and discovered my phone wasn't set up and thus couldn't receive calls. So then I added my home phone to my Google voice verification system and had it call me.
And I'm in. I put the bumper on - and I have to say that it's a classy bumper. Two colors, the fake metal bezel looks good. Not worth $20, but better than the cheap ones that I usually get.
Then my phone proceeded to update to Jelly Bean - to which I frowned because I thought it shipped with Jelly Bean. But it did that update and now I have my phone all working and I like it. As anyone who knows me well knows, I've usually been more of an iPhone guy than an Android guy but I really like Jelly Bean so far.
Sound quality is good, screen is nice, Jelly Bean is great, speed and responsiveness are excellent. The back really is a fingerprint magnet. Reviewers said it, I noted it, but like the SIM thing it's one thing to know it and it's another to go "wow, the back looks like my daughter smeared a peanut butter and jelly sandwich on it". But I'm big on screen protectors (as well as bumpers) and so I'll fix that problem myself.
So far though, I really like the phone. But I'm just getting started.