I'm afraid I can't decide on the relative merits of the Polaroid vs. Nikon vs. Canon scanners. Canon's FARE dust removal does a good job-- I have very little editing to do, and I don't use the most aggressive setting. But I scan only a limited number of negatives-- my best. So speed isn't a huge issue. Of course I'd like faster.

I don't have experience with the different slide films. Trust your eyes and think for yourself. Don't believe popularly promulgated myths. Good luck!