I've never heard the Cambridge, but have sold several of the RS520s, and think they are quite good. The GAN based amps in the 520 sound very nice, and should be a fun match with your Revels.
You likely have seen this, but the Stereophile review of the 520 pretty much sums up the unit nicely (small quirks and all.....):
https://www.stereophile.com/content/hifi-rose-rs520-streaming-integrated-amplifier-page-2
Cambridge Audio Evo 150 vs Hifi Rose RS520
I've narrowed down my search to get either the Cambridge Audio Evo 150 or Hifi Rose RS520 integrated amp/network streamer. I'd appreciate any thoughts on both. Evo 150 has more inputs/outputs and costs about $700 less, but the RS520 is 250w vs 150w for the Evo. I have Revel Concerta2 F36 loud speakers. They're not the super efficient or high sensitivity, so I'm thinking I might need the extra power of the RS520.