There's quite a long review at The Folding Society.

I tried it out and found it fairly good. The ride was better (to me!) than the older Bromptons because of longer reach, but now that the Brompton S is out they both fit me well. The Mezzo had much better brakes & gears than the old Bromptons, but at least the Brompton brakes are good now.. But neither I nor the shop assistant were able to fold the Mezzo - that says something!!!