When I get in the VUE, it does feel a bit odd. The smart is nippy and responsive in turns, brakes well, and is easy to park. For what the VUE lacks in nippiness it makes up for in acceleration and a significantly softer ride, while still handling well... and I get my sometimes missed clutch pedal, sunroof, and cruise control back. Engine noise in the VUE also is a bit unsettling... I am used to hearing the smart mumbling or growling behind me pretty much all of the time, and in the VUE you really don't hear the engine unless you are using a heavy foot (including with a modified intake)... it's a surreal woosh that drags you to speed rather than being pushed by a growling beast behind you.
The biggest things that get me when I am in the VUE are that the steering wheel rim is narrow in diameter, and the wheel itself is huge. Also, it's a bit odd that looking in the rearview mirror literally results in me looking down on people.