My 2007 MINI Cooper S is a pure joy to own. The quality is fantastic and the performance is amazing. The little 4-cylinder engine is turbo charged and really moves. Acceleration is amazing and you can zip in and out of traffic like you're driving a go-cart. It is a small car but roomy inside (unless you're in the back seat). Cupholders are tiny. It prefers premium gas and servicing usually needs to be done at a MINI dealership.
Fun factor is off the charts. I bought this car for my wife, who commutes to a part-time job. We already have two other vehicles, so practicality wasn't a concern. She decided she wanted a small convertible and after reading a lot of reviews, this is what we chose. We've had it four months now with no issues. I understand maintenance can be costly on these, but we haven't had a single issue. It gets decent mileage (it would get great mileage but it's so much fun to step on the gas in this thing), it's comfortable, and it is the most fun car I've ever driven, hands down. It has surprising room for the driver and passenger, but the backseat is only good for two mid-size passengers and even then, only for short distances.
Bought the Mini S specifically to navigate traffic congested Southern California. The car doesn't help the traffic, but it certainly makes it more fun to deal with. Supension is hard, but if you love feeling at one with the road as I do, then this is the car for you. Driver/passenger compartment is roomy and comfortable (I'm 5/10"), but back seat is pretty much useless except to carry golf clubs or one child sitting sideways. Felt the savings an a 2 year old vehicle with 25K miles made the car a great value. With the supercharged engine and auto transmission, I only average about 26 MPG, but I drive pretty hard and certainly enjoy the mileage and drive of the Mini far more than my old pickup truck. While I'll never look forward to driving to downtown LA, I'm far happier doing so in the Mini than in any other vehicle I've ever driven.