I've just bought rFactor now that they have allowed you to play in demo mode before you buy and I have to say initial impressions are pretty good.
I like the sounds, track graphics and day/night transitions so far. This is all based on about a weeks worth of play though, so I need to give it time.
The sounds are good to a degree. I won't go into all the differences between LFS and rF sounds as that's been done to death, but from a new player to rF I will say that they sound great at slow and top speeds. They tend to get repetitive around the mid range though. All the other ambient sounds are good too - break squeal, tarmac sounds, track noise, gear box whine etc.
I was training in the single seater trainer the other night and this felt remarkably similar to the FOX. Again, great sense of speed (the shaking aids this I suppose) and the engine sounded good.
Graphics are good and bad IMO. Track texture, lighting, grandstands etc are all convincing. The day/night transitions are well done which doesn't seem to affect the FPS when racing at night. The cars do look cartoony though and don't have that believable feel about them like the LFS ones.
What I really don't like, like so many reports I've read is the way you can't recover from a slide. Unlike LFS it is very difficult to control a slide (or drift) without it snapping round and spinning you off the track. This gets very annoying when you sense it's happening, but then suddenly you're off.
I haven't tried online yet, so can't say about about the netcode, but I can see mismatches occuring. I've downloaded the Nurburgring only so far and enjoying a 20Km track for the first time.
Overall, so far not bad. I'll keep trying rF as it's early days, so it will be interesting to see how LFS feels when I try that again.