PDF:s on Pads generally rock, yes. One thing, though, while probably very good for printing, PDF is a truly crappy file format for electronic display (no resizing etc.). Therefore I frequently find that I have to scroll pages left, right, and center. I think that this inhibits use at the moment. When publishers start editing manuscripts to fit a Pad screen size, there will be no reason to buy a dead tree version.
Edit: yes, you can zoom in and out, but you cannot realign stuff dynamically to e.g. keep text the same size etc.