I've only held the 520 in a store, but I did own a commander, 05 I think. The commander has one of the best grips I've ever felt on any knife, secure and comfortable. It's recurve might not be the greatest for general use though, but usable. The only time I held the 520 I was very impressed with it. -The grip was surprisingly secure to me. For day to day use, it would probably be the better choice. The 520 has the axis lock+++, secure grip, good blade shape for general cutting tasks, and a secure handle. The commander has the wave, a very secure handle, and a deep recurved edge (probably better for self-defense than general cutting). -In the end, you'll probably love either of them.