Mafate 3s here.
I love ’em. Under the right circumstances! They destroy long distance trails, and They’re excellent on the West Highland Way etc.
Steep rough ground, very poor. Steep rough contouring, genuinely awful. But they’re not made for that really. Too much distance between the ankle and terra firma.
As the others have said, they fit narrow. I’d buy at least a 1/2 size up, maybe even a full size. My feet are pretty average width, 1/2 size up was about right for me if that’s any indication. If you can find a stockist to try them its well worth doing so.
If they fit, and you’re gonna use them on appropriate terrain I thoroughly recommend them. As mentioned above, on those long 30+ runs they are superb. For me at least. The GF’s brother has been using road versions for a few years now and has completed an Ironman in them and is a keen fan and repeat customer. As I will be when mine give up the ghost.
Not cheap however.