I find that it 1. is really slow, especially for long documents or ones containing large images (so, e.g., for lengthy scanned documents it's frequently just u

I find that it 1. is really slow, especially for long documents or ones containing large images (so, e.g., for lengthy scanned documents it's frequently just unusable); 2. renders less nicely, scanned text again being particularly awful; 3. on at least one machine I have, prints documents very badly (text comes out all fuzzy, as if the anti-aliasing is messed up somehow); 4. it has no facing-pages view. I keep using it because (a) it's the default and I'm lazy and (b) in principle I like the idea of supporting a completely free PDF viewer. But compared even with Adobe Reader (still more something like Sumatra or Foxit) the experience is grossly inferior far too often.