Fine Art America is the best in several ways. I've been a member for over 2 years:

1. POD service is only $30 a year. They use top quality printers/framers. You set your own prices, they take NO split.
2. Brian, the owner, understands online marketing and gets your stuff right to the top of Google, if you're smart about tagging your images.
3. It's the only POD portal where potential buying visitors actually outnumber the (about) 30K artists. Other portals are mostly visited by the artists themselves.
4. Brian keeps adding cool new features. The last one is a complete artist's web site for each POD artist, so your visitors get all the features of FAA, but see only your art, not everyone's.
5. An image theft protection system which really works (Brian is an excellent coder)
6. Great community.
7. Lots of other stuff.