I assume you know that Sony is about the release the PRS-300 (like the 505 but with a 5" screen and a few other changes) and the PRS-600 (like the 700 but with a dictionary, hand written notes and no built in light).
If you have a Windows PC, try your PDFs in
Sony's Windows ebook Reader. The screenshots in that thread are from a version emulating a PRS-505, but the latest version emulates a PRS-700. Probably the next version (end of the month) will emulate a PRS-600 and be available on Macs. All PDFs are viewable "full page" in portrait or half page in landscape mode, but reflow only works for text and only for some text.
The PRS-700 (and presumably the PRS-600) has a zoom mode for PDFs, as well as reflow. It can also annotate and highlight, via the touch screen.