I would say no matter what both games will no doubt have both strength as well as come up short in some areas. Dirt 2 looks better and has better damage physics than Forza 3 yet Forza 3 runs at 60 fps while Dirt 2 at 30 fps. Need For Speed Shift has the most interesting in-car view as this view moves as you ram up the engine , brake, etc. Dirt 2 nor Shift has as many cars as GT Forza. No doubt GT5 running 1080p with head tracking is a plus yet it will cost somewhere else.
Having 400 to 1000 cars is a big plus yet it will also have it cost usually balance . For example, the races will either be too easy so you can take any car and win with them or too hard so you can only race and win with a select few. One of the problems with all console racers is the game has to be design around a controller instead of a steering wheel, thus easy to drive with analogs.







