Love my Diamond Goby. I never have to stir my sand. He's fun to watch, too, and not shy! I sometimes spot feed him shrimp, and he goes right after it! The only thing you gotta watch out for is having corals on the sand bed. He will sometimes dump sand on top of them. He has never done it to my big plate coral, but he has done it to Zoa frags that were on real small pieces of rubble and they were buried.
They are fairly easy to find, too.
When I was looking for a sifter, I was also suggested a Yellow Watchman Goby. IMO, not a good choice for a big tank. Somewhat timid and very small. I rarely saw him. I haven't seen him in a month or so now. Mine's a 220g.