I would say Colt if the powerport is MIM/lock.
Yes, parts may be hard to find, but if you know that in advance, you don't shoot it to destruction and avoid +P and +P+. In my opinion the S&W "Lifetime" warranty doesn't mean much. If they don't produce parts for your gun, they can substitute whatever it is they are producing at the time. You may be ok with current procution, but no way to tell what they'll be putting out down the road. For instance, if I sent back a pinned, recessed, early model S&W in for major part replacement and was told they would substitute a 2 piece barrel, MIM, lock model instead, I would let them keep their product. No offense to those who like the new models, I'm sure they have their place...just not for me.