Rob English of Green Gear Cycling (the folks who make Bike Fridays) rode across the US on a Tikit. Of course, he's a super-duper racer and ultra cool cyclist who can do most things that the rest of us wouldn't dream of. His Tikit is a very high end one with drop bars and is very light due to some carbon in their somewhere.

I would get a Tikit for urban commuting, particularly if my commute involved a bus or a train, or if there was nowhere to lock up my bike (I'd fold it and bring it to my office). However, I work from home and therefore have no commute anymore. So no Tikit, either.

I fold my Pocket Rocket Pro to fit into the way back of my VW Rabbit on occasion. But mostly it stays unfolded until I need to take it to some exotic locale, which is actually more frequent than before. Since I can take my bike, I usually do.