I've been wearing a Giro Montaro MIPS since late 2015. Luckily I haven't had to test out the MIPS functionality, but overall it's been one of my favorite helmets (Bell Super, Giro Xar, and various Specialized Helmets). The fit is great and I don't notice and different fit with the MIPS system. The one issue (and this happened with the Super too) is that sometimes the helmet and my sunglasses will bump together on a ride. It doesn't happen very often, less often with the Montaro, but it has happened on occasion.