I've read the viewfinder on the AE-1P (or maybe on the A-series entirely) was one of the brightest and best of its time. I have always enjoyed this. Even in dark situations I can see through my viewfinder better than the shot actually turns out!!
I love the ergonomics. I love the shape and size. I love the handling. You can bling it well up with flash and power winder and data back and massive zoom lense and this and that, but when you want to you can just take the body and a single prime lense and have a blast shooting.
It's not perfect, but it's darned good in almost anything you need. I can only give positive reviews, so long as you picked up one that's working, and not one that somebody pawned off because it doesn't work. Getting a full service for it can be expensive, and will probably be needed at some point down the line. I used mine for 10 years with shutter squeak before getting a CLA and I'm at 16+ years now and it still runs great. Just needs a new battery door! (lol)