TEMPUR Pro Luxe Smartcool mattress review: does this all-foam bed keep its cool?

Up until now, I’d given all-foam mattresses a wide berth. 

Former encounters with a cheap model from a dodgy website traumatised me so much that successive ones were tarred with the same brush: spongey, overheating and restrictive. The bad foam mattress I’m still trying to forget felt like sinking into quicksand and took considerable effort to haul oneself out of. Rock scrambling gear would have helped.