One of my favorite car is XRG. It's not a powerfull car but you don't need a ultra powered car to get fun, the feeling is exellent. There is not much grip and you must always be focused on the rear wheels, trying to avoid sliding in order to get a good laptime. It's pretty tricky and need a LOT of training wich is not the case of XFG i.e.. For these kind of car you must vary the among of acceleration, it's not full throtle or brake so I understand why it's a not so popular car.
I also like to drift (don't flamme me !!) but drifting with an XRT or an FZ5 is (quiet) easy, no need to know the diffrent drift's technics, just flat the accelerator to lift the rear of the car and that's it. There is a bunch of "good" drifters who think they're good but don't know, or use, any of the hardest drift technics. There is a lake of respect about the XRG imo. It's well known that underpowered car are much much harder to drift. I also think that before naming yourself a drift king you should put you ass in an XRG at least one time ...
XRT is also pretty challenging due to his massive turbo lag. You realy need time to learn the handeling of the car (for racing off course, not drifting). There is a great potential in this car: faster than the others but harder to keep on track. It's for hardcore drivers
You'll understood, I prefere rear wheel drive. FWD are much easier to drive, it's why there is much FWD driver's than RWD. But I also like XFG/FXO because FWD are much more common cars in my country and like most of LFS's player I began my LFS experience by driving FWD.
So I drive XFG/XRG/XRT/FXO, and a little the FOX.
I don't like the GTR because there is too much grip imo and I never drove such cars in real life so I can't figure how accurate the physic render is. But i'm shure that there is also a good potential of fun in these cars. I'd rather learning to drive correctly the tbo's before getting in a GTR. So maybe i'll change my mind in 6 month or more (yes I take all the time needed to build up a solid experience).
I totaly agree with BruTaLysT, there is only one 'car' wich I HATE: the BF1 (it's not a car ...). There is 1 billion wings on it, the speed is ridiculous as the handeling is. If you are smart enough to drive it smoothly you have a few chance to go on the grass for a spin. Way too much grip, where is the fun? The main reason why I don't like this car is maybe because I never found a server with good BF1 drivers. Each race ended in a major crash, in most of them I was the victime of a noob who though he was the reincarnation of Senna
I drove a few time the RB4, it's a good car but I'm too noobish with it to realy argue of what I like / dislike on this car.
So in conclusion: XRG ftw
Edit: I forgot to say: I'm an huge fan of LX4 but don't have much occasions to drive it against good drivers. Each time I drove it, it was against LX6. I don't know why but people take always the fastest car aviable. It's maybe to fill there lake of skill ... The proof is that I already beated LX6 drivers with my "little" LX4.