The F21 surf wave is significantly better than the Epic. I've surfed them both. The Epic is, as everyone says, very steep. It's kinda fun riding up to the lip and dropping in, but it's a bit too steep for good airs and, if you're a skim rider, forget it. The pocket is also significantly shorter than the F21. I experimented with adding a ton of sand to the bow, but the pocket never got near the length of the MB.
The MB wave is the best "stock" wave I've surfed. Longest pocket. With lots of peeps in the boat, it was top notch. I never surfed it with additional ballast, but I'm sure that would only help. Oh, and everyone stayed dry too.