Absolutely nothing!
Probably everything I would have wanted in a small car.
Good Points:
Performance is excellent, if not slipping against the newer hot hatches.
Comfortable interior with an array of gadgets to keep you interested.
Build quality is fantastic, no rattles and trim is well bolted together. Feels solid to drive.
For the few times I've been back to the garage for servicing and MOT, the BMW/MINI customer service has been excellent.
Appears to holds it's value very well.
Bad Points:
Boot is a bit small, but this is a MINI I guess so I can't complain there. Back seats drop down and the car becomes quite practical.
Fuel economy doesn't seem to very good round town 28/29mpg, though I managed 42mpg on a motorway run.
Are you using Imperial gallons to measure fuel economy? Are you running a diesel?
The Cooper S is a "gas guzzler" given its size, so the reviewer is either very optimistic in his reviews, or is measuring Imperial gallons and not accelerating at all on the highways.
S models are not available in diesel.