Just a quick update here. I'm currently running a weekly game that uses the D&D Next play test rules. They put out the final version of the public play test, which will make my group VERY happy to hear!(They've been very patient with my requests to rebuild their characters every month or two, haha!)
I'll post more about my opinions on the system in the future, but right now I wanted to say that currently I'm planning on picking up a copy of 13th Age. I've been reading a friend's copy, and while I'm not hugely fond of the over-inflated numbers it uses, I see a lot of interesting ideas here that make me want to try it out.
The odd part, though, is that it's clearly designed for "Epic Fantasy", which I've usually disliked as a player. Frequently, it seems to be full of unbeatable DM's pet NPC boss types and stories where the players are just along for the ride. 13th Age pushes the proverbial ball back to the players and encourages them to take a far more active role in the narrative than other d20 games I've ran, and systems like the one where you ask the players at the end of the session which elements they'd most want to see become recurrent seem like they'd lead to an emergent story that I tend to generally associate with my "old school" D&D games.