Of those I've been to Revy, Kicking Horse, and RED. They're all amazing for different reasons.
Revelstoke- I would say this mountain is best for the "backcountry freestyle" style of skiing- there's plenty of gnarly stuff too, but overall the terrain is just fun, natural jumps and cliffs everywhere, and plenty of spots in-bounds and out to build booters. Here's a clip from last year for an example of the terrain that just really lends itself to tricks:
https://www.instagram.com/p/Cnk37w9oG6U/ They get a ton of snow, and at the top of mountain its pretty high quality (not so much at the base). Sorta crowded (by interior BC standards) but the flipside is that there are a ton of great skiers there at any given time.
Kicking Horse- Just insanely gnarly and steep, I mean look at this slope shading map of the top 2/3rd's of the mountain:

Not as much snow as Revy, but its lighter and better quality. Longtime FWT venue for good reason, if you want to full-throttle big lines and send the biggest airs you've ever hit, this is the place IMO. Haven't been there since 2019, it was pretty uncrowded when I was there, not sure if that's still true or not.
RED- Overall the easiest of the three, but also the least crowded and most lowkey small resort vibes. There are a few isolated runs that get pretty gnar (like the liftline off granite peak) but overall I'd say the best for keeping it a little bit chiller and skiing as much pow as possible. Snow quality is okay, it can get a little wet and heavy but on the flipside that means it can have some super interesting skiing when the snow is sticking to near-vertical rocks well.
My favorite of the three is Revy, the playful terrain and amount of snow is just too fun and it contrasts the type of skiing at my home mountain (Taos) nicely, but I think it really comes down to preference. Definitely all worth visiting