I like the flap because it's more unique looking and more versatile. When you're done with it has a purse, if you travel you can begin using it as your carry-on bag. The flap style bags are really in right now.
Plus, I assume it has a magnetic closure and I have a Marc by Marc bag with one and I really love it. It's so annoying have to zipper close your bag all the time (since leaving it open isn't the smartest idea) so when you're on the go you simply drop the flap and it's securely closed (the magnets on his bags are super strong).
Good luck with whatever you chose!