In case the previous posts haven't helped, here's my thoughts on the F1 cars. I'm no settings guru, so most of these opinions were based on little to no changes (other than changing the ASC to 0 and the TCS in the range of 0-2)...
F094/S (NTSC) or Polyphony 001 (PAL):
Far and away the best handling F1 car. Very quick, no turbo lag because it's normally aspirated. It's a little jumpy at first, but you'll get used to it.
F094/H:
Just as quick as the above /S model, but tends more towards understeer at times when the /S doesn't.
F090/S:
The slowest in a straight line, but nice on tires and the easiest F1 car to drive. Easiest F1 car to attain, so it's usually the "starter-F1" car for us NTSC-ers.
F686/M:
The fastest car in a straight line, but suffers from some turbo lag. Suffers from a lot of understeer.
F687/S:
The next-fastest in a top-speed contest, more neutral in handling, but still doesn't handle as well as the F09x/x NA F1 cars. But turbo lag isn't as bad as the '86.
F688/S (NTSC) or Polyphony 002 (PAL):
The best handling turbo F1 car, quite nice sometimes, but can jump out unexpectedly in the tight stuff. Gets lost on the straights.
In short, they're all still better than any other car in the game, but all have peculiarties and bonuses to them.