I'd pick a (very) slight nit with your position, Harry, to the extent that PDF files that are formatted for the Reader work well enough, they're just less flexible than the LRF/RTF approach is all. If you can get the font size where you want it in the first place, not being able to change it later isn't all that huge a burden -- all that's my personal opinion of course, so salt to taste.
Either way, Hadrien's putting forth a yeoman's effort with FeedBooks, and I'm sure it's a perfectly suitable solution for some folks, and if others find they prefer something else, well then I'm glad that both options exist.
I think we had some reports of ~10 hours of battery life with MP3 use, but I'm digging way back in the old memory file for it.