The hottest would be the EC-120.
All that glass and no ventilation, apart from a piddly fan that just blows in your eyes. No good in an Oz summer. My feet, in black shoes, were in direct sunlight and felt like they were on fire. Had to fly with left hand on cyclic and right hand trying to scoop air in through the piddly sliding window. Back seat pax were really suffering.
Had an S-76B at 185 kt briefly (Vne 155 kt) but that's another story.