We have been going to WCPP for the last few years.

Fewer people go there than Q, there are some motors, planes and cabins. Q is generally more scenic, especially than those areas affected by big forest fires in the 80's. WCPP is more rugged and therefore more wilderness-like IMO.  

Fishing can be great or terrible, depending on the body of water.  Some good sized lakes are too shallow/sterile to hold fish.  Some lakes have walleye, some areas of the park don't.  Very few hold SMB. A fair number hold LT, pike are everywhere other than the sterile lakes.

Ontario camping permits are required, just like Q.  No reservations are required.

For great information contact Claire Q or Doug Gilmore  at woodland.caribou@mnr.gov.on.ca