Well, I've got a few miles on it now (2,732, to be exact), and I'm bored at work, so now seems to be a good time for an update.
Service: I changed the oil at 2,000 miles just to get the stuff that the engine broke in with out. Oil filters are expensive, and it requires dexos1-certified oil (so dino oils in general and some synthetic blends are out). Used my employee discount on some full-synthetic Quaker State oil, and still paid $22 for the change. While I was underneath it, I removed a plastic tray that ran underneath the entire engine bay, as a) under-car servicing is nearly impossible with it, and b) GM stopped putting them on after the first of the year anyway (my car is a November '11 build).
Recalls: My car fell under two of them so far. One was for replacement of the fuel filler neck, and one was to reposition the airbag in the steering wheel. Thankfully, mine didn't fall under the infamous missing-brake-pad recall (seriously, look it up).
ICE: Sound quality isn't too bad from the stock stereo and speakers, but it still is a bit tinny and quiet. I'll live with it for a while, but I have a feeling that the sound system will be revamped eventually. My free trial of SiriusXM satellite radio ran out, and I decided not to renew it. This was a good idea, as three days afterward I got an email offering me a year-long subscription to the service for half off. I fully plan on taking advantage of this.
Driving: Rev-matching is still difficult, especially during the 1-2 shift, but I'm rapidly getting better. It's also quite the hypermiler; I was able to average just over 50 MPG over a mostly-highway, 80-mile round trip. When I'm not babying it, however, it will definitely get up and go. Also, dat turbo whine.
It also handles pretty well, but the stock tires really hold it back. If my Drag wheels fit the Sonic, with the Falkens on them, I would have way too much fun with this car. As it is, I still have a lot of fun with it, and I don't regret buying it in the least.