TL;DR: still looking for a hard-working reef-safe emerald crab!
Oh, that's good to know. I'm going to be organizing another group buy in a week or two. Need more emeralds and a tux...
So far, my experience with ReefCleaners emeralds has been +/-. On the plus side, none of them have been coral eaters. On the minus side, they seem to be territorial in my 10gallon tank, and I always end up with the same one lazy emerald that started out as a good cleaner but is now an off-and-on cleaner--it sometimes eats bubble algae, but it's also quite happy to steal food from the RFAs (that I target feed). Every time I add a new emerald, I find it belly up in a couple of weeks with one exception...
The big emerald from AquaSD. Ordered one along with a fungia plate and torch, and it was a bubble algae EXTERMINATOR that the resident emerald didn't mess with. But... it liked to taste every single coral it walked by. Grabbed it out of the tank when I caught it green-handed with a torch polyp extending right from the torch into it's mouth. That one was donated to Tong's.