The latest info I saw posted at RWA was that at this time, Samhain was only working with agented authors. Maybe that's incorrect, but my agent had no problem subbing to them. He's in the business of making money, and pitches my work to markets where money seems to be being made.
And a growing component of Samhain's market is in print, especially since they have entered a mass-market print distribution arrangement with Kensington. Plenty of agents pitch to Kensington, and Kensington books generally don't pay large advances, either. And in general, most of the money agents make on the romance market as a whole is in the earn-outs, not in the advances. That's how my agent looks at it, anyway.
Many of the e-pubs may not pay advances or pay only small ones, but the earn-outs on their titles (especially erotica) can be MUCH higher than the earnings on a print romance title that doesn't earn out its advance.
Some agents shy away from the e-markets, but a growing number of agents are seeing how lucrative they can be (especially erotica) and are therefore looking at them more closely.