I've gone back to using TrueGrip. I just prefer its balance of characteristics. For me, it just has the right amount of thickness, weight, feel etc. And it just works well with overgrips without increasing the grip size too much.
ShockShield is useful if you want to add weight to the handle, damp out some of the feedback and don't mind slightly increased thickness.
Good to have different options really, but I guess everyone's looking for slightly different things.