Nobody can agree on whether one needs exposure compensation or not.
My FM2n came with a K2 screen, and I replaced it with an E3 (I prefer not using a split-prism). I measured a 1/3 stop difference between the two screens, the E3 being brighter. Test for yourself.
Oh, and I agree that focusing with slower wide angles can indeed be challenging. The Nikon F2 series has the best viewfinders for that application, in my opinion.