Well, my face-to-face group has gotten up to 15th (starting at 3rd) and it has been fun all the way. I was worried the game would overpower in paragon like it did around level 13 or so in 3.5, but so far it has not happened. The numbers are getting pretty unbelievable, though. I know I have an AC of 30, but still, when the monsters have +22 to hit, I still feel like I am doomed.
But the powers are interesting, and the combats word, even though we fought something with 600 hit points a short while back, it was a decent fight, though we did notice the grind the last 200 or so points.,
I voted Paragon, as I have not even really looked at Epic, or gotten close to playing it.