I originally wanted a Keyfit, but then I felt it. That baby is HARD. I certainly woudn't want to sit in it for a car ride. So many seats are lacking comfort, it's no wonder babies don't like the car. So, I was stuck deciding between the Companion and Safeseat1...they were the only ones I found with any kind of cushioning. We will be moving from NY to FL shortly after baby is born, so I was especially concerned with comfort for a long car ride. In the end I went with the Safeseat1 because we originally going to be driving to FL to my parents' for a couple months and then flying to Puerto Rico (where we were originally being transferred) and I wanted to be sure the baby would fit in the seat until then. My kids are notoriously long early on, and even with the newer height limits on infant seats, there was a good chance it would be outgrown. I got the Safeseat with memory foam in it and it is soooo nice and cushy feeling. I really think people overlook the baby's comfort in a seat when shopping around. Safety comes first, obviously, but after you decide what you feel is safest check for comfort, too.
Also...those of you whose babies outgrew the seat too early to use the bucket in a restaurant, etc...when DS outgrew his snugride at 3mos, I got him a RA and kept his snugride in the trunk for those random times we needed it, like shopping if he didn't want to be held, or sitting in a restaurant where I wanted a clean place to put him down.