I liked the Cohesion 3 a lot better.  The Cohesion 5 is a lot lighter, which might sound like a good thing for a running shoe, but it's a training shoe, not a racing shoe, right? The Cohesion 3 felt better cushioned and like better protection for my feet, especially for training on hard roads and/or the hilly, wooded cross-country terrain here in my native Connecticut. The Cohesion 3 was more comfortable. Also, I bought both in the exact same size, yet the Cohesion 3 fit perfectly, while the Cohesion 5 seems a bit too small, so Saucony's sizing is inconsistent, which is disappointing.