Yep, the length of career determines what teams you start in, for example I'm doing 7 season and am in a Lotus. Do 3 seasons and you get to choose one of the top, 5 and one of the middle teams.
The handling is superb. It's a bit buggy, but the pit stop bug, for example, can be overcome by pitting at a different time to the AI. It's not one of those games where the bugs hold it back a lot, certainly not how I've found it.
Seven seasons is the most you can have, isn't it? Anyway, regarding the handling, how does it stack up to GP4 for you? This is one of the most crucial points for me. Also, does the AI try to stop you overtaking and is it easy to look sideways at someone to see how close you are to bumping wheels with them?
Regarding the pitstop bug, I read on Codies' forum that they're already on it. Maybe the patch will include an option to drive the damn car in the pitlane yourself - it's AI controlled right now, isn't it?
This is a sort of fundamental thing they almost certainly won't fix with a patch as well.