It would depend on the type of PDFs, I suppose. For PDFs with complex layouts and lots of images, you'll probably want an ereader with a larger screen size anyway.
For novels and the like, reflow has become essential for me. I know some people have had bad luck with reading PDFs that don't reflow, and I can't speak to most 'homemade' PDFs, but all the PDFs I've checked out from my library -- okay, not that many, probably just twelve -- reflow correctly. Depending on the text size, I usually have one page full of text, the next page half-full, then repeat. This means that you sometimes see the PDF's header in the middle of the page, and it might be a distraction for you. I'm okay with this because I really hate panning otherwise.
A
non-reflowed PDF v
reflowed PDF. From what I understand, the Sony supports the forcing of reflow even if the PDF isn't tagged properly, resulting in the first example. For PDFs that are tagged to support reflow already, it's more like the second.