My wife rides the ‘original’ Peloton (without power meter) alongside me when I’m on the rollers and/or Kickr. She does 5x per week, and absolutely swears by it.
Ours is ‘non-power’ based, but the interactive classes are a bunch of fun and always have new/fresh music to listen to. I use it a few times per month. The “road feel” is pretty lousy if you’re used to a proper trainer, but getting the fit/measurements correct is quite simple. It’s just the flywheel thing feels mushy (to me) and there’s no possibility of back-spin or freewheeling because it is directly connected to the crank.
For me, it’s a diversion from the monotony of TrainerRoad (truth!) but it’s not in any way useful as power-based training. It’s aerobic. It’s fun.
p.s. @gpl reviewed some cool pedals last week which I already ordered for our Peloton, so I can wear my normal SLD-SL shoes, and my wife can run SPD ‘spin bike’ cleats. (At the moment, I wear SPD cleats when I Peloton rather than messing with pedal swaps – but thanks to GPLama, those days are numbered!)