I played the barebones version of Lumines for PC. Plain and silent, it isn't a great deal of fun. If Polarium had some insane visuals and music I think it would win hands down based on what I know about the two games. That being said I still need to experience Lumines on the PSP and see what all the fuss is about. PA's comic on it makes me even more eager.
But Mercury shall rule supreme.