I've been to both. I actually prefer Wapati in Jasper but I think I'm in the minority but if you can get a site by the river it's pretty nice and you can watch the rafters go by. They're across they road from each other so the location is great for sightseeing trips. If you have the time do a trip out to mt Robson, I'd suggest going as far as Rearguard falls. It's only about an hour.
I've stayed in Mount Kidd once, not really my cup of tea. It's more of a resort. It's a great location though with lots to do around it. Make sure you go up to the lakes. There's a campground up there called Interlakes, I like it a lot but it's very difficult to get into.
