I instructed in one a couple of years ago, and had the chance to drive a couple of laps in it at Summit Point. Absolute BLAST to drive.
The only drawback - they are completely a one-dimensional car. They were built for one single purpose - to turn. And turn well. But like ashen said - if you are in that 0.001% of the population that puts turning above all other aspects of driving, then the Elise is for you.
I believe the folks at Lotus made a deal with the devil on that car - all you need to do is think about turning, and the car is turning.
Personally, I would love one as a daily driver. Then again, I don't consider myself to be part of the 99.999% of the population....
-Z-man.