I haven't stayed in any of them. However, I have visited Blue Mountain many many times. I enjoy going to Collingwood. It's nice. But I don't feel that the Blue location would be on the level of many other exchanges as far as feeling like you are at a "secluded" resort away from everything. It's set up like a small village. Collingwood has many options all year round. Golf, lake right there, skiing of course.
I would think that the downtown Vancouver location would be fantastic. Views, on a high floor, would be breathtaking. I've seen the CI location..great. Downtown Vancouver is totally contained. You can walk everywhere. Transportation is exceptional. I love Vancouver. So beautiful and so much to do. I am so excited to go to CI there one day and back to Vancouver in general.
In the other Canadian locations (Whistler, Mount Tremblant, and Blue) they all tend to look very similar to me (village layout). MT is extemely low points (and on the week exchange as well) and would be feel "away" as it is a French speaking area. Probably one of the oldest.
Well I'm not a lot of help. Hopefully, someone will be on soon about actually staying in the suites.
Good luck.