Well, in general, I would handily recommend the Motorola S305 because they're inexpensive but deliver excellent audio quality for the price--and especially because they serve that dual purpose so well, listening to stereo audio and making phone calls with good sound quality. They are, indeed, very light and they're reasonably comfortable--better than most bluetooth stereo headsets I've owned or tried. You certainly couldn't go wrong for the price. You can probably do what I did and get the Samsung later for those other times when you want to just bliss out to some music--but in the meantime, the Motorola are an all-around better purchase for your first pair. That's my opinion, anyway.
I'd still rather have the option of using a mouse and keyboard, since there are those times when it's far more ergonomic or faster than tapping or swiping around, bringing up and putting away a virtual keyboard the whole time.
But really, just be sure to turn off whatever you don't think you need--turn off GPS, WiFi, Bluetooth, etc when you're not using it and the device will run for hours upon hours upon hours like it did for me on the trains. (Although, I had the luck of always having AC plugs in the train for all but one of the legs of my trip).