The sizing is comparable to my Salomon 3D XA Comps. But I went up 1/2 size on the Mizunos -- I am finding I like shoes that have at least 1" beyond my longest toe. Also the foot box is wider. I think my feet swell more with minimalist shoes on long hikes. 11.5 Salomons are a perfect fit, and I went up to 12 with the Mizunos; and if I bought another pair of Salomons, I would probably go with a 12 too. With all of these shoes, I never have blister problems, except for one instance I will share a little later in this post.
The Wave 4 insole is thin, thin, thin and glued in. But they are minimalist shoes... replacing the insole kind of defeats the purpose?
Traction with the Wave 4 is not stellar. Craig and I descended a knarly canyon (think glisading on loose rock and soil for a thousand feet at something like a 30+ degree grade) and he was much faster, as his shoes had better traction. Or maybe it is that he is half my age/more agile/conditioned/confident/less risk adverse?
If I need great traction on a trip... lets say steep descent with lots of loose sand and tiny pebbles on granite, then I wear Sacouny Peregrines these days -- they are the best traction shoe I have. There is a trail I often hike that has an 8,000' descent over 11 miles. I will slip a few times with the Mizuno's, but not at all with the Peregrines. I doubt there is another trail in the continental US with this kind of descent so don't take it as a the norm. I ripped an expensive pair of nylon pants on this trail with the Salomons, and broke a LT4 using the Mizunos on it too. Both were on descents... I don't slip on this trail going up.
And no rock plate with the Mizuno's. That can be a concern. About 3 years ago Craig and I did a 60+ mile 3-day trip with a 20K foot elevation gain/loss and I wore a pair of Sacouny Shay XC flats, very light. On day 1 I had a impact injury to the ball of my foot. The morning of day 2, the entire ball of my foot was one huge blister. So this is the chance with light shoes and no rock plate. And the injury was not noticeable at first. Felt like the mid sole of my shoe had cracked and was pinching my foot... just a minor irritation. I inspected my foot a few hours after I first noticed it and I could not see any injury. It felt like something was wrong with the midsole of my shoe, not an injury.
Everything is a compromise. I have a pair of New Balance MT101RX. The traction is between the shoes mentioned above (Wave 4 and Peregrine). It has a rock plate. But my go to shoe is the Wave 4 whenever possible. In tough conditions it is usually the Peregrines or Salomons. I haven't warmed up to the NB yet, and not sure if I will.
I have a pair of Vibram KSO's and hate them for hiking. They are okay for running on nice trails. My little toe hits obstacles and they are hot and sweaty. After a few days they stink to high heaven. But if you like talking to strangers, wear the Vibrams... strangers will stop you and ask about them :)