I'm using a thudbuster on a Dahon Vitesse with a 2.15" Big Apple Liteskin on the front wheel run at a low pressure. . . it's not a bad ride but I'd still rather have a Jetstream if I had the cash. The roads in east London are pretty terrible. I've been considering trying to improvise a suspension stem but I can't find the right seat post to use as a stem.
Having said that the Jetstream is a little heavier than my bike and doesn't have an IG hub, which I like a lot. And a downtube FS would be too heavy. . . so my bike is a reasonable compromise. . . and a suspension stem might be the best overall compromise as it'll not add much extra weight.