i had a supercharged cooper s and it was a good car. it did follow cambers a lot but thats just what you get with a short wide car with wide tyres.
it had excellent handling, good brakes and gearbox but was let down by interior quality/rattles, harsh ride (run flat tyres are sh!t) and a pretty boring power delivery and shocking fuel consumption. i think the turbocharged version would be more fun and the JCW now has a diff which the cooper s didn't. oh and the TC was so intrusive it was a pain in the wet.
i would have loved a test drive in one but couldn't and decided something slightly more grown up would be better.