I switched from the endorphin speed to the zoom fly as my workout shoe in my last marathon build. I found the endorphin speed was pretty useless before 250 miles, so I wanted something more durable. I also have ankle problems, so I was looking for a heavier shoe for stability. The zoom fly has held up past 250 miles, and I think it’s pretty decent overall. It’s definitely a little stiff and heavy, but if you train in the Pegasus you should be used to that. I like it for workouts, but definitely wouldn’t want to run in it every day.