The suit is well made and the hood/veil arrangement is way better than the Oz Armour version. I would expect the Oz Armour suit to be cooler because it's more like a net curtain, this one is thick, breathable material. My mate carries an epipen and has been wearing a hoody underneath his BBwear suit so I expect him to be a lot cooler.
I noticed two more examples at the Welsh Convention, one was by BBwear, best described as two layers with small holes everywhere. These small holes have a fine mesh in them but I reckon two of these holes aligned would not prevent a sting, especially with the material pulled taught. I can't remember who was selling the other suit but it was similar to BBwear but resembled a space suit.
Speaking as someone who overheats very quickly I can only see any of these being cooler if there is a breeze. Without a breeze I can see me melting as usual.