You don't have to carry anything to listen to music, podcasts, or audio books with the wifi-only Apple Watch (beyond the bluetooth earphones, presumably), and it tracks your run too. The thing has 16GB of storage and a full ability to exist by itself. I've never used the S3, or the Garmin, so I have no idea how great they are, but I just had to comment on the Apple Watch thing.

There are some things that the Apple Watch seemed designed to be tethered to an iPhone, almost like they were (bizarrely) afraid that it would make people not want to upgrade their phone. They've taken a really rapid approach away from that, though, and the watch is becoming dramatically more powerful by itself, even though it could already do all of the basic things.