womble, I've been using Sigil for a little bit now.
It's the only thing I've got that opens Epub's other than Calibre's reader function.
I probably will get the Firefox add-on that Bohica was so kind as to inform us about, but I just really haven't needed to bother yet.
My take on Sigil is that-
It's free and updated periodically
It's a powerful editor for Epub that you could probably read with if you wanted to
It's NOT a program to convert formats with. (Yes I know it probably converts to HTML or whatever)
It will allow me to fix covers, TOC, and other things if I take the time to learn how.
It will NOT open some Epubs, that Calibre will, and errors out with a message - I have no clue why.
Nevertheless, I have it associated with Epubs on my computer and wouldn't be without it.
It goes without saying that Bohica and Merry will probably be more able to advise you on its use than I can...
