I used to prefer LRF because it supports full justification and header and footer, but now I am more on the side of ePub.
LRF is an output format. Once you make/get it, no further editing is possible, unless you convert back to something else, losing all formatting in the process. In the past, for each book I made, I used to keep the original text, plus a BookDesigner html0 version, plus the LRF. That is, 3 versions of each book, in case I wanted to go back and edit something.
OTOH, ePubs can be easily edited with a text editor or (better) with Sigil. It is Ok to keep the ePub version and throw away everything else.
Although LRF supports font embedding to some extent, page turning is noticeably slower, at least in my 505. With ePub you can use font embedding without performance loss. I discovered that using the font I like is more important than header/footer and full justification.
Besides, ePub is more future-proof than LRF.