Thanks for the thoughts/opinions. I went and looked at all three today. Didn't like the Pria at all, and between the Peg and the Nextfit I liked the Peg a bit better. The Nextfit was easier to get in the car, but the Peg was easier to get the kiddo into. I thought the Nextfit pull strap was really hard to use (to tighten the harness), and the shoulder pads seemed to cause some tightening issues too. I also wondered how hot the seat would get. The Peg was definitely harder to get into the car, but not too bad.
I also had a chance to check out the Clek Foonf. I didn't get a chance to try that in the car, but I might go back tomorrow and give that one a shot too. It seemed stouter than the others, but I almost wonder if it was too open. I think the biggest potential issue is the height of the shell (will I be able to use the rear-view mirror). I doubt I could use the rear-view mirror with the headrest all the way up, but by the time it gets to that point I'm sure the seat will be on the side instead of the center position.