That's a very good looking bench. I think I may follow your lead, if you don't mind. I was thinking of doing the 44"x44" Kreg set up to use as a general assembly/outfeed table and build some drawer carcuses underneath for storage.
What did you finish the MDF with, it has a very slick look to it (almost looks like hardboard)? Also, how did you fasten your maple trim to the MDF? Did you put any cross bracing under the MDF so it doesn't sag over time? How are the Kreg frame and wheels holding up to the weight you've put on it thus far? I've built a similar general purpose table and use 2x4s, but I really like the idea of using the Kreg framing system because I can dissassemble it if I ever wanted to in the future (I think I'd need a bulldozer to disassemble the one I built as it's built like a tank). Also, I read that Kreg's framing system is much sturdier than say Rocklers.