veinglory is absolutely right, because it does fall on the popularity of the publisher when all is said and done. This is not to say that the author doesn't have to get out there and shake the universe to draw attention. But sales with a publisher involves many factors: Length of time in business, name brand recognition, publisher publicity and marketing, quality of product, reviews, awards, competitive price, past and current sales record, number of authors and titles, and other factors.
Ellora's Cave and Sanhaim are just two very prominent e-book publishers who have established themselves and do quite well, in fact, they can be considered leaders in the industry. (Visit Veinglory's site to get some really neat info on stats and performance--she's also a damn fine author--nobody knows this side of it better than she does).
This is my first e-book. Ever. I have NO idea what's up with this kind of publisher. I only know that it HAS to be better than what I went through with my past two print publishers--BELLY-UP--NO SALES AT ALL. So anything I pull will actually be a miracle to me. We'll see. So far Lyrical looks fine, with no real complaints, and they meet certain ethical criteria. In comparison, they are fairly new, which means author participation is very important. For instance, AW Lyrical authors should stay in touch with each other, link up, and market as a group whenever possible. Share review sources, enter contests like the Ippy (sp?), keep a blog going, take advantage of and join display sites, but remain active and current on those display sites. Join groups or organizations pertinent to your genre. Announce/list your titles in any and all free libraries (AW has one).
With any e-publisher, it boils down to what you put into it, you get out of it. We all have to make that effort. Money just doesn't roll on in. You have to make things happen.
So far I'm very impressed with the editorial side of Lyrical (That's as far as I am along the process). I'm getting slaughtered, which is DAMN good for me, because somebody is taking the time and using precision to make this book the best it can be. We don't know what the future holds, but we certainly can impact it and tilt the odds for a favorable outcome.
Good luck, all,
Tri