Sigil is by far the best "epub reader" I know. When I compare for example Adobe Digital Editions with it, Sigil is the only one able of copy and paste material (except links and pictures) into a word document in a correct way.
The funny thing is, calibre is also an awesome programm too, but guess what.... it can't hightlight any text neither; don't ask me why
So anyway, I'm happy for the great work there has been done with Sigil !!!
Thanks