I have one in my tank. I see him every once in a while. He stirs up the sand really well, only thing is if i have something stuck in the sand he will knock it over or move it around. A few weeks ago took a cute picture of one of my hermit taking a ride on this back.
I know Capp Bay gets them ever so often.
I do not have lots of sand areas for him and I would strongly suggest that you have plenty of sandy areas for him to dig through, so try to get a small one. Might be better off checking a LFS to see if you can find a right size for your tank.
Mine has lived for well over 6 months now....