Riding in a warm, humid climate, I chose the non-MIPS version of this helmet for lighter weight and maximum comfort, and it has not disappointed. It feels feather-light (my large is marked as 255 g) and ventilates so well that just walking while wearing it produces a noticeable breeze. My head feels like one of the coolest parts of my body while riding. The retention system took some adjustment and getting used to--in particular I had to lower the adjustable head basket a couple of notches from the default position in order for it to tighten adequately. With that done it fits securely, tightening via the top dial in a very diffuse way that does not create pressure points but stays in place well. I have no complaints and would not hesitate to buy again.