For me I'm a huge fan of:
-Skunk cleaners: clean fish, reef safe, and most "outgoing" non-shy shrimp
-Peppermints: stay small, never worry about aiptasia, most passive
-"burgundy hermits": they are the best hermit crab I've found sofar as they are less aggressive then blue-legs and are constantly moving.
Not a big fan of:
-Mantis: although "reef-safe" in the sense of coral, they will crush any other living thing when they get big. i.e. CUC, fish
-Coral banded: although some "play nice" I've seen enough of them bully and get aggro at other shrimp/CUC to make them too inconsistent for my liking.
Unsure of:
-Mithrax crabs: I have 3 in my 55g and I haven't caught them doing any dirty-work yet but I hear enough to worry me. For me though they really took care of my random nuisance hair algae etc.
-also pistol,camel, blood/fire shrimp, since I have no experience with them.