I test rode a Tikit, but they only had the old style stem and cable system. It was definitely flexy and loose. The rest of the bike, however, rode extremely well. Way, way better than my Giant Halfway.
In looking at the Bike Friday Tikit... I think that for me, the Model T might be better. The simpler design means you never have to worry about that cable going wonky on you.
I also had a chance to test ride a Brompton M3L. I wasn't sure what to expect, but I found the ride to be good. The gearing is surprisingly pretty wide for a 3 speed bike. The ride is a little bouncy though, and I'm not sure I like that. I would also need the taller seat post as the standard one felt way too short.
I would say between the two bikes it's a virtual tie... Both bikes seem well put together (except the old style stem on the Tikit). They both ride well overall (with the Brompton having the bouncy issue which is honestly minor for me).
I declined to ride a Birdy as it was well beyond my price range. I also declined to ride a Dahon Curve as I am above the weight limit. They had a Mu SL which I now wish I would have taken for spin, but I can do that some other time I guess. They didn't have any other Dahons on display or I would have test rode one for sure.
All in all, I would definitely buy a bike from Rapid Transit... and if I decide on one of the ones they carry, they'll definitely get the sale. Very friendly... and knowledgeable. The bonus is that if you buy $1000+ bike from them you get 2 years of service for free.
Wish I had a chance to see a Swift in person to really judge how big the folded size is. It appears enormous in pictures, but it's really hard to judge it. Would be nice to find a pic of a folded Swift with a folded Dahon or other 20" folder.
Anyway... the most important thing to note is that I'm driving to work these last few weeks... and it really bites!
--sam