Mrs Ewazix has a Cooper S Coupe.
Likes
Strong engine with great torque as the turbo is very linear
Fantastic grip. Handling is rock solid providing high cornering G with zero fuss
Huge boot
Good MPG
Sport button actually does something in terms of adjusting performance and opens an exhaust flap for a rorty exhaust note
Dramatic styling
Dislikes
Ride is a bit clattery
Engine is rough and many owners have had problems with timing gear faults, idling issues, fuel sensitivity (97 RON) engine lights and coking up
The low roof line makes it cramped and VERY uncomfortable for me at over 6'2"
Interior rattles
It's an easier car than the Z4 to run across country on challenging A / B roads and I would back the S to see off all but the most talented driver in more powerful cars. But TBH I don't like it and actively avoid driving it because of the cramped seating position for me lack of refinement. The Cooper S is definitely a hot hatch feel rather than sophisticated sports car and a completely different experience to the Z4. I haven't driven a JCW but reports are that it's even more hard core but I have a horrible feeling that I would tire of it quite quickly. But if it's your thing I can't think that much would keep up with it