This is an interesting topic, truly.
In my opinion, if a car
game (I count all publically available simulators as games under the simulator genre) can be driven with a steering wheel (and preferrably with a clutch pedal and a H-shifter) and it doesn't
try to be an arcade game (such as Trackmania, NFS) it can be compared amongst other driving sims.
Having driven all the public car sims (IR/NKP/RF/LFS/GT5P), I can say each of them have their own ups and downs. The downfall of RF is the physics department and the finesse with the FFB delivery in means of feedback of what the car is doing. In return of those, you get a great open to modding base which requires people who know what they are doing.
Niels' Corvette was the eye-opener for me in the case of RF, and after discovering the oversteer mod, I could finally start doing big slides in RF without spinning out of control every single time. Using the realfeel plugin, the force feedback didn't feel too far from the real life either. With these two mods along with a proper twisty mountain road, I was enjoying RF quite a lot for a while. It wasn't realistic enough to keep me coming back to it, but it was couple months worth of very good fun.
I bought a PS3 last year just to try out GT5P, and it didn't really dissapoint me, too much that is. What I was expecting, was just another GT4 update with prettier graphics on top of it, but how wrong I was. They had upped the ante with the FFB which was now acceptable enough, but the physics were still a bit so-so (notorious GT4 open diff syndrome still exists at low speeds). Still so, I could actually feel what the car was doing for the first time ever in a GT-game. If you want to see how it looks when driven with a proper wheel, I grabbed a
video of it.
The big letdown of GT5P isn't the physics, but the multiplayer. There is NO way to host your own private races, only multi racing you get to do, is the public nightmare. Only way to join a server, is by random, you have zero control in which host you want to join. And with the usual luck, the game throws you in a server filled with players who have no idea of proper car control. One time too many did I get rammed in to a wall from 1st position by a 13-year old pad player just to drop to the last spot.
GT5P vs. rFactor.. I think they are more or less equal. Neither of them have physics or FFB nailed down perfect, but they are both acceptable enough to have fun with, as long as you have proper mods for RF.
Anyway, I guess the only advice I can give to the OP is, try out all the games yourself before anything. I was very sceptical of GT5P before having a go at it myself, and it was a positive surprise.
