Recently ordered Armlocks for All Styles, by some guy called Iain, never heard of him before, but he shows potential ;-)
As I do Ju-Jitsu I have found it extremely useful as having a Karate background Iain shows the striking opportunities, which rarely get shown in Ju-Jitsu (as it was developed by Samurai to fight other Samuri wearing armour).
Have now ordered Throws for Strikers, which may seem strange, surely doing Ju-Jitsu I should know how to throw! Well, yes but there is a big difference between throwing people wearing a Gi and people wearing a T-Shirt. Once your oppoennt is wearing a gi you tend to get an over reliance on the gi and can und up with some throws which woud never work outside the dojo.