I have spoken with Greenleaf and am waiting for their proposal for my book. Not sure I will go this route yet, just considering both avenues including traditional and hybrid publishing. They seem legit to me. Yes the cost factor is there, but they know the business well and they only take about 10-12 out of 1,000 submissions. I'm only considering because if you go traditional, if you're not a well known author, the bulk of marketing will be on you. A publicist is about 5,000-6,000 a month...if you hire one for 6 months (which I know from other areas in my life, you need to have publicist start 6 months before opening/publishing to get the momentum going) So that's $30,000 right there. The major publishers put the bulk of marketing money into the established authors that they know they will see big returns on. So, you will be left to do most of your own marketing. Even if you don't hire a publicist, you will still spend at least 5,000-10,000 trying to market yourself and the results will be less than stellar if you're not a professional marketing expert. So, again, no matter how you slice it, you are dropping big money. I would rather pay that to an established company with a sound marketing plan and include the fact that they can get your book into physical bookstores and libraries, which you won't be able to do on your own.
Anyhow, it's a personal choice that I haven't made yet. But out of all the hybrid publishers out there, Greenleaf seems to be the most legit. I have looked at Manhattan Publishing (I think that's the name) and they have a fancy website and look great on the surface, but then I researched and found out that their parent companies (they have multiple) have had lots of lawsuits, so I'm Leary of them.