The serrated wheels are also supposed to track better. I think this is less of a problem with today's high-quality abrasives and grinders. I don't have any finish problems on a serrated wheel either, but I will say that I prefer a smooth wheel in the large wheels 12+. I've used 12" smooth side by side with serrated (the 14" I've only used smooth), I just prefer the smooth wheel on large wheels. 4" - 8" I like better serrated, have also used them both ways. 10" I've only used smooth, but I don't really think I'd have a preference.