With the neoprene ISO versions unavailable four months back at my supplier I opted for the more expensive Outlast version - that is lined with the orange coloured phase-change material that's supposed to absorb heat, then give it up as your feet cool.
They have been quite a disappointment. Not only has the rubber construction of each of my last four pairs of Aigles been thinner than the previous pair, but in the latest the Outlast material doesn't - and I'm sorry about this - last. After just four months of wear once a day for an average of about an hour, the liner has worn through under and around the back of the heel in both boots. You know that feeling when a seed works its way under your foot in a wellie? It feels just like that.
They are not a rip-roaring success.