Except when you have pdfs that use certain funny image-compression things that make it look fantastic in Acrobat and xpdf-based viewers; Preview does horribly o

Except when you have pdfs that use certain funny image-compression things that make it look fantastic in Acrobat and xpdf-based viewers; Preview does horribly on those. I agree in general about Preview, though. (It might be jpeg2000; I just know that when my dad scans a book, it looks good in acroread and xpdf, but in Preview it's very slow and pixelated.)