I have 2 Bromptons.
If I were to do it again, I would go for a Bike Friday, Dahon or one of the new Brompton clones coming out of Asia.
The paintwork on Bromptons is notoriously bad. They have a habit of releasing Brompton 'Specials'. A change of colour paint is not special.
My main concern is that the Brompton drive train is very unique. If you go touring on a Brompton. You need quite a bag of special spare parts with you as they are not available in bike shops.
Some of the Brompton clones are now getting good reports. They have standard drivetrains, better gearing, disc brakes, wider tyres. Things that Brompton should gave addessed a long time ago.
I ride my Bromptons regularly and I like them. But I think there are better folding options.