After another couple of commutes using the autosteer, I've decided it ain't ready for prime time. If I wanted to spend my car time terrified, I'd be a driving instructor.
Besides not handling merges very well at all (it'll brake hard if you let it go to the last second, but that, you know, sucks), it lost its brain a couple of times, wildly oscillating between the lane markings until I had to grab the wheel. Lanes were clearly marked, with cars in front and both sides. Both times, the road was curving (very slightly, this is a freeway) and traffic was moving about 35-45mph.
Not worth the aggravation yet - I'll stick to TACC, which is actually quite nice in stop and go traffic.