I wouldn't get one unless you have a HUGE tank. Like several hundred gallons. Not because they're expressly bad, but because they're sand sifters and can pretty much clean out your sand bed in fairly short order. It sounds like a good idea at first until you realize that they're practically sterilizing your sand bed. The same thing goes for sand sifting stars, IMO, which are not to be confused with the detritus eating varieties.
There is also the issue that once it's done that to your sand bed, it'll die and rot.
