Agreed with the negative reviews of the 15’s. Brooks has done something do the toebox that now makes the Adrenaline 15’s unwearable for me, and they felt stiff. After only 5 miles, I had blisters, which has never happened in > 5 years wearing this model. I complained to Brooks and was told to go up a 1/2 size, but I already wear these a full 1.5 size larger, and when I go up another 1/2 size, the arch support isn’t in the right place and the shoe slips. Brooks said that I will like the next model better. I don’t understand why they would introduce a shoe with such a sizing discrepancy.