Nothing will beat the ride quality of my Rivendell of course but I am not that happy with my Dahon. For long distance the Dahon is fine but when speeding through traffic or attacking the hills I find it very flexy. It doesn't bother me as much as it did when I first got it and I now attack the hills in the saddle but I would like to have something more rigid, more comparable to full-size bike. After browsing the internet I had the feeling that Tikit and Swift might just do the trick. Also my gf would need a folder and she is fond of the yellow colour of my Dahon and I am always happy to upgrade my bike park
Haven't ridden Brompton in 10 year so I don't remember how the ride compares to other folders but I have and LBS that carries Brompton so that shouldn't be a problem. Never looked in to Mezzo but I'll check out that upgrade thread.
Haven't given Moulton a thought actually. I have tried Moulton a few times and was smitten by the
smooth ride but I have a feeling that it would be stolen pretty soon. For the same reason I have rejected Airnimal which also has a brilliant ride (have friends who have done 600 km rides on their Airnimals)