I'm currently a 645M owner and looking at the Fenix 6S Pro as a potential upgrade.
At the moment, if you want a fully featured "small" Garmin watch your options are Forerunner 245, 645 and now Fenix 6S. I've compared photos and the dimensions of the 645 and Fenix 6S - screen sizes, bezel size, case size - are all identical from what I can gather. I welcome the redesigned case, reduced thickness, reduced weight and the shorter lugs - it's a nice looking watch, especially the "Pro" in black or gunmetal.
I am interested to know what quick release strap comes with the Fenix 6S. From the photos it looks like it's marginally wider than the 645 strap, which will be a welcome change as it will offer more support for running than the F5S strap did, but I can't tell what length it is. I found the strap on the Fenix 5S to be almost too short for me - guy with a small wrist. Does anyone know the total length with it on the watch?