[Sealevel]

Got a pre-spec with leatherette. I've had a chance to try 5 of the available US materials during several visits to my dealer in 83-88 degree weather, not all of them apply to the S though. Comfort in hot weather was the primary concern, so adjust accordingly for your climate. For what it's worth:

Gravity leather--S. Initially too warm after sitting in direct sun (and probably too cool after sitting in the frozen tundra) but adjusts quickly to climate controlled temp, and breathes well. I was really thrashing this S demo without paying much attention to seats but the slightly grainy texture didn't seem too slippery. Good adjustable lumbar support. With some experience of midwest winters as well as Florida summers, this is a good all-around choice.

Leatherette--S & Cooper. Not a cheap vinyl!! High quality and good appearance, easiest to maintain. Sitting in direct sunlight with AC off, it was initially okay but got uncomfortable quickly. Adjusted to climate controlled temp okay and stayed comfortable thereafter, but seemed the least breatheable of all the materials mentioned here. Maybe a better choice in more moderate climates. Grainy texture, not slippery when throwing the MINI around. If your back needs TLC, definitely arrange a long test drive and see if the fixed lumbar support works for you. Adjustable would be a smart future addition given the wide use of this material in both models. Maybe too critical of this one because I've had the most time in it.

Profile leather--Cooper. Even though it's black, I sat for over a half hour on an 85 degree day without the AC on, after the MINI had already been in direct sunlight for several hours. It was remarkably cool and breatheable under the circumstances. I think those silly little dimples promote better air circulation and would be equally adaptable in cold weather. Good adjustable lumbar support. On a short but spirited drive it adjusted quickly to climate controlled temp, there was no tendency to slide around, and was very comfortable. Okay, so the texture is a little weird and it looks like the hardest to maintain (keep away from children with food) but IMO a very good all-around choice. More so if a lighter gray or tan was also offered. If it was available in the S it would be my first choice, at least until an attractive half-leather option came along.

Kaleido cloth--Cooper. Most breatheable, coolest, but least "classy" & lack of adjustable lumbar support is a minus. A marginal choice without sport seats.

Smooth leather--Cooper. Cordoba beige only, very cool sitting in direct sunlight on a hot day, lighter color probably helped. Seemed like it would get slippery though, sport seats a must. Good adjustable lumbar support, very comfortable. Should be an S option IMO, a classic with BRG!