[quote="kitkat"]and to add on to that question.... do you sweat more in leather???[/quote]
Despite what people think about leather being a natural material, being able to breathe etc etc, in my experience on a hot summers day it makes bugger all difference whether you have cloth or leather seats. (leaving them in the sun notwithstanding).
They are both going to make your back/bum hot (temperature wise - not sexy sizzle hot. If you want he latter go do step classes). The best cure I've used for this problem is to simply lay a fluffy towel over the seat to help get some extra air between you and the seat. Stopping every now and then also helps to air the back and seat.
Cloth wins hands down for grip, but suede (or alacantra) offers similar levels of grip as cloth and also has the durablility of leather. PITA to clean and maintain though. I hate the OEM leather seats... anything more than coasting pace and I slide all over the place in the seat. the seat belt doesn't help here either... I'm sure a 6 point harness will go some way to fix the problem, but nothing will hold you better than a fixed bucket... so on the shopping list will soon be a Sparco but that could be a while yet... maybe sooner if I win the lotto...

RDM