I was a die-hard supporter of cloth over leather. I live in hot so calif desert, thought leather would be too hot like vinyl seats I've had in the past. I also argued that cloth holds better for the twisties.
I now own two roadsters, one with cloth, one with leather. I still believe the above is true, but by far less than was my initial belief. In the leather MSM both points are almost mute in the leather. If I had to argue, cloth would still win, by by a thin margin.
The biggest winning point for leather is:
Major ease of getting in and out of the low seating postion, and adjusting your body to a comfortabl seating position. The low seats of a roadster have you drop into it, and this is accomplished much much easier in a leather seat, try it, it is a significant factor. You drop into the seat and slide the last few inches into the seatback against the leather, this is a friction probelm in cloth. Then the pivot to get the legs in is a smooth slide vs a friction probelm again in the cloth.
I also sit higher in the leather seat. WHy, I don't know, different cushion, or firmer support from leather. Just thought I'd mention it, food for thought.
I'm a converted leather lover, so cal sun and everything. Too each his own for sure, but try them out a lot if you can before you decide.