I have tried iannotate but I strongly prefer pdfnotes, they have a free version that is fully functional and I use it for everything. Textbooks, reading papers, and even importing blank pages for random note taking purposes. It does a great job of handling several gigs of pdfs, zooms great, writes smooth, multitouch shortcuts, and options galore. You can easily export annotated or original pdfs to email/dropbox or other apps.
MynameisMike: I don't see a problem for left handed users, most of the time when I write with my finger or my stylus my palm doesn't touch the pad so it shouldn't matter much.
MynameisMike: I don't see a problem for left handed users, most of the time when I write with my finger or my stylus my palm doesn't touch the pad so it shouldn't matter much.