by movesets not personal prefrence
Mew can learn any TM/HM, so you can give it the best moveset you can think of.
I have to agree, mew it can learn any tm/hm you can think of + the only pokemon other than ditto to learn transform
Jirachi owns in lead wrecking with Trick/Choice Scarf
I never played with the others, so I vote on Jirachi