I had heard about Draft2Digital taking on Smashwords in the e-book distributing market. Now there’s a third company joining the competition: Publish Drive. All these services are ways to distribute your book through several channels with one submission.
There definitely was an opening for competitors to Smashwords. The service’s guidelines and requirements for manuscript formatting are a little over the top and difficult for most authors. Seems like there is always an error or unmet formatting nit waiting to trip you up each time you attempt a Smashwords upload.
As a new alternative, Draft2Digital does the formatting for you. Just submit your file and they take care of the rest.
This article from Kindlepreneur, linked above, provides an intro to each service, plus a pros-and-cons comparison.