Well, according to Zwift, I've an FTP of 252, which the should mean a 20m test result of 264, which means a w/kg of 3.3. That agrees with what Strava says on recent rides. With that set of numbers, the 6am rides with Laurens Ten Dam leave me pretty knackered (read fvcked, massive pool of sweat, soaking wet, but still able to commute to work). I have to put out about 240w on the flat and 300w+ on the hills to keep up. If I get dropped, it's touch and go whether I can get back on.
I think as it moves beyond the early adopters, the groups will become more representative of normal cyclists. About 5 people in my club have signed up over Xmas.