I saw one recently @ CapBay and was told they are extremely easy to keep. (Although the one they had was NFS because it was dying.)
Was told they'd have more in soon and they're about $12.
Rarely satisfied with info I receive from the LFS, I came home and did a little surfing and bookmarked http://www.advancedaquarist.com/issues/july2002/toonen.htm">this site</a>. I've skimmed this article and decided to put off getting one of these until I learn more.
Good luck and keep us posted on how yours does. If you learn anything more about these guys, please pass it along.