rFactor is pretty rubbish compared to other sims. Some of the mods themselves are fine, but they're still limited by a physics platform which still has its roots buried in 1999.
On a basic level rFactor is good... but it's diluted compared to some other sims. iRacing is about 10 times better, but it isn't for the casual sim racer, which is where rFactor is generally aimed at. Don't get me wrong - it's not some arcade racer masquerading as a sim like RACE or the old CMR titles.
The main problem with rFactor is that for every good mod, there are 20 awful ones... and the online servers are clogged with people racing the rubbish ones, while the decent mods (like the 1979 F1 one) are fairly unpopular.
How did you manage to break my quote that badly?