I myself had this debate and am going with the Marmont Camera Bag, purely because while stylistically I love a flap bag so initially I wanted that - I don't like that the Marmont Flap is not structured and kind of squeezable if that makes sense (it is quite malleable). I can see it losing it's shape eventually, which would really disappoint me because I love more structured bags generally.
The camera bag is spacious & still gives me the Marmont vibe, but is definitely more structured & fits enough for daily use - it's the perfect grab & go bag imo!