This time of year, perch can get kind of wormy. The only time I usually will eat them is during icefishing or very early in the season. I've talked to some who will eat them any way. They say cooking them thoroughly is okay, but I am not sure I would. yuck!
I caught a nice perch two weekends ago on Mille Lacs and cooked it up and I could not tell the difference between the perch and the walleye. It was a jumbo and came from fairly deep water, so the meat was real firm.
Actually Quinndog that perch would taste much better then the Walleye if it were winter, Mille Lacs perch are buy far the best tasting Perch around Winnie is pretty good "in the winter" and I hear Devils Lake is Great also.
I don't keep and I rarely eat any fish after June and I would definitely not eat any Perch in the summer other then maybe Mille Lacs.
Yep, the thing to look for is the black spots. This can become very prevelant this time of year, especially on some lakes. From what I have found, it seems that the warmer the water, the more likely the spots.