I'm no Samsung fan, but I have to hand it to them. Their implementation of mobile payments will probably be more successful than Apple's. I love using Apple Pay, but it's a year out and I still have to remember the few places I can actually use it.
Ironically, Apple and Samsung seemed to have flip-flopped in the ways they've rolled out this new feature. Usually, Samsung, in its mad rush to be cutting edge, implements a new technology in a non-user-friendly (or even sloppy) way, and Apple swoops in a year or two later and does the same thing, makes it simple for the user and it's a hit.
In this case, Apple made Apple Pay fantastic to use, but has thus far failed to create the infrastructure to use it in. Samsung comes in, implements nearly the exact same feature and makes it useable anywhere by using older, already-established tech. It's interesting how this has turned out.
Anyway, Samsung Pay might be more successful in the short run, but my guess is that neither Apple Pay or Samsung Pay will be the winner in the long run.