Comments: I logged just over 4000 miles in the boston 3 and developed large calluses on the medial ball of each foot, so the wider toe box of the boston 4 is much appreciated. I slipped the boston 4 on for this mornings 19 mile run. The forefoot feels more firm than the boston 3 and there is less forefoot sole flexibility, which adds stress on the calf muscles. Could this be from fewer striations across the sole? My foot was warm and sweating the whole run, which rarely occurred in the boston 3. I attribute this to a less breathable upper material. The material feels closed off, especially in the toe box. Once again, I have been disappointed with a new model year shoe. I am going to have to find another go-to shoe for everyday, high mile running
Comments: The 4 seems to be a tremendous upgrade from the 3. The fit is much better. I had to wear a 12 in the 3 and an 11 1/2 in the 4 is much more comfortable. The 4 has more forefoot cushion but seems more flexible. Both shoes have great response but I think the 4 is faster. I attribute it to the flexibility in the midsole and the upper as well as the slight weight reduction. Admittedly I was skeptical that Adidas had screwed up a great shoe like they did the Ace after the 2nd version. Wrong. Great trainer!!
Comments: very comfortable and light
From: Jackie, San Leandro, CA, USA
Comments: After 50 miles in the shoe I can say that I am really happy with them. I am a big fan of the Boston 3's which do feel different than the 4's, but not in a bad way. I like the tongue on the Boston 3's better, and my foot feels more secure in the 3's too. The 4's have a great ride. I've done tempos and a couple medium to long runs in them. The 4's do feel lighter and the upper is very breathable. The 4's are a bit softer than the 3's and you can tell there is a bit more cushion under the ball of your foot. The toe box is wider too. As a trainer, the 4's have been great so far (only a week of use). I will update this if things change. I could use these as a possible marathon shoe. Shoe feels lighter than the 9oz it is.
From: Andy, Houston, TX
Comments: Have to disagree with Andrew from Atlanta. The toe box on these is noticeably smaller than the Boston 3. I don't know if sizing up a half size will compensate, but I had to send this one back. And I like a snug upper.
From: Drew, Nashville, TN
Comments: Shoe feels about the same weight as the boston 3. Definitely feels more like a trainer than a racing flat, and slower than the 3. It is wider on the sole in the front and heel than the 3, which is probably why it feels slower. Toe box is slightly bigger than the 3's, it also feels slightly more cushioned than the previous model. Depending on what you want out of the shoe, the update is either great or bad.
From: Andrew, Atlanta, GA
Comments: These are incredibly similar to the F50 Runner 2 from what I can see. That's a compliment, even though the F50 marketing never took off in the U.S. Will give these a look in a few hundred miles.
From: Chris, Boston, MA, USA