My first published book was an ebook collection of my erotic short fiction. I picked the publisher based not on any previous experience with them but because I liked their design sense and because they seemed like they might be a good fit. The collection was accepted and I turned out to be mostly right about the design sense. On the one hand, I got a lovely cover and the ebook looked pretty good and actually got some editing (the majority of stories were reprints so they'd been edited previously). On the other hand, I got a cover and a title that didn't tell prospective readers about the content. This was also a clue that they would have no idea how to market the book at even a basic level.

At the time, I didn't realize how important this would turn out to be. The only reviews it got were the result of me, not the publisher, contacting people I knew and asking them to review it. The publisher did manage to nominate it for a sort of catchall award but none of the others it would have been eligible for. And there was no other effort to reach an audience for this kind of book (lesbian erotica, in this case) since it fell outside the standard scope of what the publisher had done to date (gay erotic romance). As it turned out, there were some additional issues about what titles did get plugged and what didn't, but I didn't know this at the time. 

 For my part, I plugged it on my blogs and website and published excerpts and so forth, but didn't tap into some of the available online opportunities because I had yet to discover them. The upshot was that the ebook sold almost no copies and never went to print (the award for being a best seller). A subsequent version of the book done in both print and ebook outsold the total original ebook sales (over a 2 year window) in about a month.

I did learn more about self-publicizing from the experience, though, so I can't say it was a complete waste. I also learned a bit more about selecting a publisher on their track record instead of going by the superficial criteria I used intially. Some things to look for:

What do other authors say in private about publishing with them?

Where do their reviews appear? Any awards? If so, are they ones your book might also qualify for?

What's featured on their website/blog, etc.?

Are the books a good quality product - clearly edited, easy to read on the page, nice covers, etc.?

And of course, how much do you enjoy their current titles? Chances are, if you think more than half their other titles are either not very good or not to your taste, you won't be happy with the results of that publisher producing your book either.