I have been doing this for a few years (Since 2007).... here is the list of the bikes that did not make the cut.
- Montague Paratrooper - 1 year - Great bike... not train friendly
- Bike Friday pocket rocket - 6 months, to clumsy in the fold , but nice to ride
- Dahon 7 speed - 2 months ,heavy, terrible up hills, did not like the gearing, not sporty enough
- Dahon speed 8 - 5 months, not as heavy, nice ride for steel... bit clumsy for the train
- Giant Expressway 2 - 6 months, Very sporty with a trekking bar, fold as good as a Dahon... nothing special
- Citizen Miami - 1 month, heavy... did not fit right.... rides like the Dahon 7.... eh
- Dahon Silvertip - Nice ride... eh fold for the train.... might as wekk get a big folder
- Mezzo 10 - 5 months, lighter, nice fold, sporty ride for a small bike, did not like the riding position
- Brompton S6 - 1 year, I know... WOW.... great fold, train friendly, ride ok, luggage ok, my big ass feet hit the rear roller wheels to much, caused knee issues
- Swift - 4 months ... liked the ride, hated the fold, did not like the rack system, got in a bad crash.
- Bike Friday Tikit -2 months... did not like the ride, the fit was eh... the stem was to wiggly for my weight.
- Dahon Espresso - Present bike.... got nothing but good to say about it... a full size folder that is a bit bigger fold than the Dahon speed 8

Some of these I had at the same time. I feel like a serial folding bike killer.

The espresso.... nice bike... nice ride.... goes on the train ok... subway fine... back of the acura great......