i havnt driven a mini or a smart.. but i have got a morris 1100 s which is basically a four door mini with a 1275cc cooper s engine, and while it is a great car, and i spent alot of time and money making it work, i still think the 126 is hugely more fun to drive. the morris has character too, but the 126 is "cute" and nothing gets peoples attention as much as that. plus a 126 actually seems to get more female attention than other cars because of the cuteness.. girls die for cuteness.
i make myself sound bad there, i just want to clarify that i have only been with one girl in my life and im still with her. i am judging by her reaction and that of my female friends and people who my friend and i have come accross on our travels.
also, minis use more petrol. and my morris definately does, though it is still great for consumption.
buy an isetta:P