I’m using the none disc as my winter bike, bought at Christmas and 2000km on it so far.
Initial thoughts are that I like it: it’s a lot more like my summer bike than my Kenesis Tk2 was, which just seemed to suck energy. The RT90 is light, comfy and seems quick. I’m actually looking forward to trying it without mudguards in the spring. The only thing to be aware of I’d say is that some of the builds use a stupid 35mm bar and stem combo which makes it hard to swop stem lengths, and Garmin/light brackets don’t fit.
Btw the RT 80 is identical apart from the carbon layup so it’s about 100g heavier.