I'm a dick. I couldn't choose. Initially I almost chose MP because my least fave from that, Vital Signs, wasn't enough to set it behind my two least faves from PW, Entre Nous and Different Strings. Also I REALLY like all ten remaining songs from the two albums combined. PW contains the first song I ever heard by them, Freewill, my alltime Rush favorite, Natural Science, and Jacob's Ladder is just cool as shit. MP, while not containing the killer's row emotionally speaking that PW does for me, is a fantastically consistent album front-to-back.
I tried listening to the "weaker" tracks thinking this would give the two albums some separation and it made it worse. Now I actually like them all. You could say I won.