The transition from 20" to 16" wheels was more dramatic than going from 700c to 20" for me. Riding a 20" bike doesn't feel too different from riding a fuller-sized bike, but going down to 16" was an entirely different experience in terms of twitchiness and bumpiness. I've gotten rather used to the ride by this point, but if I didn't have to do multi-modal commutes, I wouldn't ride a 16" bike by choice.