I always consider PDFs really awful for this. They always end up MUCH bigger (in file size) that you anticipate or want, and that makes them unwieldy to email. Worse, you can't control the zoom level that they open at on your client's screen, so the images NEVER look their best - they're usually blown up beyond 100% and therefore look blurry.
Much better, in my opinion, to create a private web page, then provide them with a link to it.