I've published 15 books on Smashwords without difficulty. My wife has a nook and I have a Kindle. They look beautiful on both readers.
It takes some patience, but in little over a year, my free stories have been downloaded tens of thousands of times and my books for sale have been purchased hundreds of times through Smashwords and it's retailers.
It's not as easy as Amazon, but if you're willing to take the time and put in the work, it's most definitely worth it. My experience has been nothing but good.
Also, people complain about it taking weeks or even a few months for books to be distributed to retailers, but it's still 10 times faster than traditional publishing. Much of it depends upon perspective.