It get rediculosly hot in Brisbane, and the exposure in australia is way higher than in the states. Sometimes the seats in my 8 get so hot (black leather) that I burn my hand on my wheel and the shifter (alum bazzle on top) and my gf burnt her thigh on the seat (not Physically burnt skin that left a mark but way to hot to even touch let alone hold body part on)
That being said I would prefer mechanical (not electric) leather seats cus they are light and they don't get dirty. My old seats had stains from various beverages.. These ones I just wipe