Is one paragraph of suspense long enough? I thought so too. I bought the Canon EF 70-300 IS DO USM lens today - Canon's only DO lens, and as far as I know, the only real DO lens out there with any decent optics. No, I won't claim to be an expert on Diffractive Optics, not by a long shot.
Anyhow, some quick notes on the lens: it's heavy, it's wide, it doesn't actually fit well into my Crumpler 4 million dollar home (my camera bag) if I have my other lens (EF-S 17-85 IS USM). On the other hand, it's short - VERY short. Unless you have the lens hood on it, however, as the lens hood is nearly as long as the lens itself. That was a surprise for me.
Not being one to leave a toy un-played with, I've taken a few pictures already. One of which was a picture of my monitor from across the room. The impressive part was zooming in to read the text, and see the mouse pointer. I think I'm going to like this lens. Keep an eye open for a few new pictures on my gallery, once we get a decent sunny afternoon.