The Carbon / Black base seats in the Cooper S have a very similar cloth to the base JCW ones, but look closely, the cloth stripe is subtly different and the seat design is very very different - the bolsters are not as deep, its a standard adjustable headrest, no adjustable leg support and no Dinamica (Alcantara) elements to them.
So yes, JCW ones are fundamentally different to Copper S etc. and be careful if speccing a JCW, only the Dinamica / Cloth (base) and Dinamica / Leather (option) are 'true' JCW sports seats. All the other seat options including full leather are 'normal' sports seats.
But the two JCW options are structurally, physically identical I believe - its just the covering is different. So depends whether you like a bit more leather and a bit more red in the cockpit.... £1400 seemed a lot of money to me at the time for a bit of red leather and an extra bit of Dinamica, so I stuck with base and I absolutely love them. £1400 far better spent on the exhaust!!!!
Had some nice half Leather / Alcantara style sport seats in one of my Audi's but the kids trashed the Alcantara bit with general child dirt, sticky fingers, food etc. Still a concern, but they've grown up a bit and tend to do obey they no food ban now.... so my seats should last well!