Well the R series and the CR-x40 (not 2040) all use STK i/c amps which tend to die at some point and are hard to find or unobtainable. For that reason many folks here stay away from them.
Also some don't find the tuner sections in the early digital attempts to be as good as the analogue tuners.
On the other hand the CRs have 40 year old caps in them so may be starting to go. But that can be restored with readily available replacements, just takes money, skill and time.
So on a reliability scale, the CRs are better.
Sound wise, I can't comment other than I find my R-900 to be pleasing and has been for the 32 years that I have had it. Lately it baked an STK and some related resistors, but it was fixed. It still has some other issues that I haven't pinpointed yet, FM can get noisy sometimes, intermitted distortion and a pretty noisy phono section. I like it enough that I will have it recapped some day.
For me, I would be happy to own a CR 2020, 2040, 1020 and I would give an R-1000, R2000 or R-9 if the price was right. The bigger R series have even more reliability issues than the lower line models but selling prices usually reflect that.