No way to convert any ebook without first removing the drm.
But I have to ask, what is it you don't like about epub? I read a lot of epubs on my reader and have no complaints. One thing I've heard that lrf does and epub doesn't (yet) is full justification, but I actually prefer non-justified text. Other than that, I don't think you'll see much of a difference.
Also, if you have questions, privately asking people who might know usually helps
