I've been dealing with Achilles issues for a little over a year. I ran a spring marathon in Adidas Bostons, and my Achilles were toast afterwards. I then ran a fall marathon in Next%s, and my Achilles were not nearly as bad afterwards and I was able to start training again sooner.
I land on the outside of my heels, and I do notice at slower paces the Next%s force my heel to immediately pronate in. At six minute pace though they're totally smooth, by the time I've pronated I'm already on my toes.
By the way, has anyone else had issue with the Boston 7s and Achilles soreness or is it just me? Even after workouts they cause noticeable soreness, I now do all my faster stuff in New Balance 1400s. Maybe the forefoot is just too narrow or not supportive enough?