I still think the OP cannot afford the Brompton which is why he's trying to convince himself the Mezzo is better. I used to do the same thing with my old Dahon Piccolo by saying there was no difference in quality. Boy was I wrong!
The only thing I regret is not buying the Brompton sooner! The price is not going down so get one while it's still cheap! LOL! When I started looking at the price of a Brompton, you could get a C3 for $600.00 USD! Not anymore.
The OP will live in regret if he spends his hard earned dollars on a Mezzo. He'll end up like me trying to convince himself, he got the better bike but in the end, there will always be deep resentment everytime someone with a Brompton crosses his path.
Don't put yourself through that agony.