Regarding the campground, never stayed there, though the same office handles Poe Paddy, where I have stayed. Poe Paddy is a more primitive campsite, and right on Penns, both which appeal to me more than the more "improved" Poe Valley.
Note that Poe Valley was shut down and underwent construction/renovations in the past year or two. They drained the lake and worked on the dam but also apparantly did a lot to the campground and other facilities. Hence, older reviews you get may not be accurate anymore.
That whole valley is a beautiful location.
Regarding the fishing, it's your standard stocked lake. Could never pass up big wild fish in Penns to fish for stockies. There's a few wild brookies mixed in with stockers in the stream below the lake. Above the lake, it's not a bad wild brookie stream, but it's a patchwork of private land till you get WAY up.