They're in the same family as the Queen Trigger, they also look somewhat similar to the Queen too but not as aggressive as the Queen. When they came around awhile back, in the 80's, they were somewhat aggressive, similar to the Huma Huma Triggers. As they got large they became more aggressive, as most triggers do. Check Reef Central as there are a # of people that got them the last time they came around, so they should have them for a couple of months by now and should be able to give a good opinion on them.
Also some of the size that first showed up were pretty large, 6"-8" range, which is pretty big for a trigger. I've seen some smaller sizes for sale recently, 3"-4" range.