Well, I recently embarked on the adventure that is R3E. When I first tried the free content I was in awe of the visuals and sounds, but the "feel" of the car just wasn't right. Very floaty, no feedback from the tires. I've read through all 24 pages of this thread to see what others have gone through and experimented with and eventually I got a FFB setup that felt much closer to what I want/expect. It's still not perfect, but it's good enough I can enjoy it. I found that the Understeer setting made the biggest difference in getting the feel I wanted, a setting of 35-50 seems ideal (depending on the car) and I also turned a little engine vibration on to simulate the feedback I'm not getting from the road surface. My FFB strength is 68-70 (depending on the car), FFB effects at 135, Vertical force at 200, Lateral Force at 115, engine vibration at 35. I also adjusted the parameter in the text file as many recommended, that seemed to make some improvement.
This game is schizophrenic though, some cars feel great to drive and some have the floaty feeling no matter what settings I use. I got the DTM 2014 for a good deal (bought 2013 on the black friday sale and then upgraded to 2014, around $25 total which is less than 2014 by itself) and the cars feel pretty good, but still a bit floaty. Still fun though, good enough to enjoy.
I also bought the Daytona Prototype along with Mid-Ohio and Indy and that car on those tracks feels great, almost exactly how I want/expect it to feel. So I decided to do some competitions to test out some other cars. Tried the ADAC BMW Z4 and it had a pretty pronounced floaty feeling, which was disappointing considering most people say those cars feel great. Then I tried the BMW from the WTCC pack and that car felt almost perfect! If all the cars in the game felt like the WTCC BMW I'd buy all the content without hesitation. I've read that some cars/tracks have updated physics so I'm presuming that's what I'm encountering here, but I'm not sure if it's the car or track that's making the things feel correct. Hopefully the updated physics feel like that BMW WTCC car, if so then there are good things in the future for this Sim.
But at the end of the day the online multiplayer for these titles is pretty much non-existent from what I've read and that's going to prevent me from investing much more time or money into the game. That's a shame because of the Sims I'm playing right now I keep getting drawn back to this one when I just want a fun AI battle. But at least I can have some fun races at my two home tracks (Indy and Mid-Ohio, I live between the two of them and have been to both multiple times) whenever I get the urge.
TL
R With effort the FFB can be made to feel quite good on certain cars/tracks, but the lack of a robust online multiplayer system will prevent me from investing much time/money into it for now.