It depends on what you like.
Some complain about the Smart being way too bumpy while I stiffened my suspension.
The lifetime cost of the Smart is lowest in
a recent lifetime cost analysis for both gas and hybrid vehicles.
Do you need power? Some think the Smart to be underpowered (it would be if it kept the older European 40hp instead of the new 71hp engine) yet many of us routinely leave people far behind when the light turns green.
Some don't like the automated manual transmission. It's easy to take manual control over the no-driver-clutch mechanism but many people expect it to be just like their grandfather's automatic.
There's an unusual amount of space in the Smart both in room for the driver and passenger as well as grocery, luggage, even a full set of tires without folding the passenger seat down which you could do if you need more space.
Do you like safety? While it's small, it's no death trap. Take a look at safeandsmart.com for more info and real stories about how Smarts performed when they had to. I like that we're a smaller target and the structural reinforcements are substantial such as the square tube steel beside the occupants in the door.