Like Rain, Se7en is a performer - he steps on stage and he can make absolutely anything sound fantastic. That's exactly what he did with Better Together. I first heard the audio of this and I was like "blegh, ok, next album", but then I saw it live and my jaw literally dropped. Nevermind the annoying siren sounds and the strange outfits the dancers were in - the song, and Se7en's vocals, sounded brilliant.
If there's one thing Se7en has over Rain, it's the vocals. I mean, Rain's voice is fine and his live vocals are stable at best, but Se7en's were just consistently strong. If he wasn't using a handsfree mic, I would've exploded with joy and admiration.
But back to the song. Now that I've narrated how I came to like it, I'll go out and say that I like it better than the Rain lead single. A lot better.
It's nice and upbeat and fun and all, but it's also slow enough to lay down an actual melody, then actually hear it and have someone sing it - it's humanely possible to sing the hook, and I think that's important in a pop song that you're pushing to the masses.
Like I always say, regular people like you and me have to be able to sing, or even just hum, the melody of a good pop song - it's supposed to stick to their heads, but you'll know a pop song is effective when you have people actually sing it. People actually sing the hook of this, therefore it's an effective pop song. Add that to the fact that I really like it and you have a damn good song.