In general, we've loved all the RS hotels at which we've stayed (10 tours.) Our least favorite was in Rome, but it wasn't the Aberdeen. We love the Aberdeen. The one we cared for least was the Nardizzi Americano, which is just down the block from the Aberdeen. And really, the only thing we didn't care for there was the breakfast. Bad vending machine type coffee, no bread the first day. Actually, bread did show up - just as we were leaving for a group excursion. The second day there DH and I brought fruit and rolls to share; the next day a number of other tour mates also brought goodies.
And yes, I know Italians eat a minuscule breakfast, but this breakfast was unacceptable.
In general, though, we've appreciated the variety of hotels on RS tours. Yes, sometimes the room is small (even cramped,) and sometimes you luck out with a corner room and sea views. In all the hotels, we've never had a dirty room, and only once did we have one where the noise really bothered us. (Clattering vent fan in the bathroom at the Hotel Torre Guelfa in Florence. The fan came on automatically when we hit the light switch, jerking the other person awake. We learned to, ummm, manage in the dark.)
Quirky, family run, centrally located, stairs, little or no air-conditioning. It's all in the catalogue.