I use both ePub and LRF. Most of my books right now are in LRF, but I'm starting to use ePub more.
I like the fact that I can easily embed fonts in ePub files without any hit on performance. I don't really like the page numbering system of ePub files--especially the page number on the right hand side of the display, but it's not to annoying. I don't really have a preference between left and full justification, once I start reading it doesn't really matter to me. I do wish that the table of contents was more quick to access in ePub files--I will be exploring this more.
dordale