I have a pretty good puff at my school, and the 2 summarys above are pretty much exactly how I play the match up.
the #1 Thing about this match up is to knock puff away from you and charge your shot. 90% of what I do vs puff is zone them out, rack up damage, then go for some sort of hard nair, fsmash, dsmash or something that knocks puff far away from me, and just charge the shot. will almost never edge guard puff, so theres no reason to spam missiles or anything, she can get around them too easily. If you have a shot, and recognize where shes going as shes coming back on stage, you can try to shot her as **** touches the ground to refresh jumps.
Another thing is that I normally go for weak missiles. puff can get around power missiles easily with her mobility but weak ones follow her and put a little bit more pressure to avoid them.
Another thing is that nair is super good vs puff. if shes coming from above you, depending on the spacing you can flat out beat anything shes going to throw at you with a good nair
Last thing, almost never grab. Its simply not worth it cause missing it is a guarenteed rest