I've kept a lot of them (larger hermits other colored legged), still have a couple stone crabs to catch. The only issue for me was the acro eating limpets. But they don't reproduce fast and you can just pick and toss them. I gave them a chance as some are OK, but one killed off a piece I had. It ate a path right around it. I also think I have a larger pistol shrimp, that though most don't believe I think ate a fish. An older reefkeeping magazine mentioned they can.
Even with the headaches i'd still do TBS again, the life that is there is amazing and my tank avoided diatoms, cyno and other normal startup issues so far.
John