I find
Project Gotham to be more arcadey, filling the gap between sims and Ned for Speed/Juiced/GRID/etc. The cars handle better - less realistically so.
While GTR and Grand Prix Legends were good sims on the PC, they're getting a bit old and you needed a good wheel to get anything from them.
The Gran Turismo and Forza series have provided a decent level of simulation with cheap hardware, not as punishing or as detailed as the PC sim titles, but as good as it gets with a joypad and a telly. I admire the way they concentrate on the racing, rather than distracting me with game modes and style points. I find those middle-ground games as much fun to play, but when I want to just race, this is where I come.
In RL I've done some karting and rallying and the earlier PC Colin McRea games were
way more realistic then the more recent DiRT.