Can't fault either if looked after well

. The bis is a little rarer in my eyes... somewhat because there were plenty of other offerings on the market in the 90's. The space in the back is incredible with the back seat down and the heating is nice

. An air cooled may be a little cold in the winter months but I wouldn't want to treat them to the salt on our roads too much anyway.
Air cooled, parts are plenty available... late 126p's built tend to be a little rusty as they were poorly sealed in the factory. I think an 88-92 model would be best... that or a well looked after or restored earlier model.
Vinyl seats in the classics and cloth in the more modern.