I bought my last pair of Ronins this week, the Mizuno Wave Ronin 5. I wrote about this shoe in my post on the Hitogami. This is a shoe that a lot of runners aren't familiar with, but it's been my favorite for the last few years. I'll miss it, but I do like the Hotogami which will be replacing it.
From left to right in the picture above is the Ronin 2, 3, 4, and 5. The Ronin 2 was my favorite. I liked the fit and feel and even liked the yellow. I wanted to like the Ronin 3. I live in Baltimore and this shoe is black and orange, Oriole colors. For some reason, I didn't like the shoe as much. It felt too tight in the forefoot. I liked the Ronin 4 much more than the 3 despite its looks. The shoe felt great. The Ronin 5 is very similar to the 4. I don't feel quite as secure in the shoe. I prefer the lacing on the 4 better than the 5.
Mizuno changed the bottom of the shoe also. The Ronin 4 and 5 had flex controllers. I never noticed them one way or another, but I heard some runners say they didn't like them. It seemed like the rubber on the 4 and 5 was also harder. I wish the outsoles were made of slightly softer rubber. The shoe was very durable. I would have been willing to sacrifice a little bit of that durability for better grip.