well replace a converter is a heavier work, but less bolts involved, no gaskets and cleaner job.

Replace cam will mean drain water, remove stuff with gaskets that could need to be replaced, if A/C equipped probably you doesn't have a recover can so will lost it, remove radiator and condenser if thats teh case, more lines etc...

all depends at the end if you are concious that's what you want because you really like the cam