I've had my Smart 4 days now and I love it! The only time I'm aware of how small it is - is when I look at it, not when I drive it. Sure is easy to turn around if you miss a turn! Still getting use to the feel of the transmission.
I feel a little obsessive about keeping it clean - I keep wiping it down. Also a little paranoid about parking in public. Does that subside after a while?