I have to preface this by saying I have only had melanurus wrasses because I liked the look better:
Which is better:
•Pest-eater - Both melanurus I had were great at this
•Peacefulness towards tank mates- First one was wonderful, second one was a terror that killed my barred hamlet (he was traded into the LFS with full disclosure)
•Coral-safe - Both were coral safe
•Ornamental inverts-safe - First one was, second one was not
•Hardiness - Both were extremely hardy (first one just died of old age earlier this year, he survived my many beginner mistakes)
•Size - Both maxed out around 4"
•Tank size - First lived his whole life in a 65g, Other one lived in 150 until I had to deal with ICH, then moved to 65 where he killed my fish
•Tendency to rearrange - Neither did this to me
•Looks: Hands down Melanurus - this is why I never tried the Halichoeres chrysus