I have used both Split Jaw and AML.
Initially, I liked Split Jaw best but having used many more AML, I find them easy, fast and reliable. They're smaller so disappear into my ballast better. Importantly they are also cheaper, and with their recent special offers, have been very good value.
I do have Split Jaw tool, which is OK, but I use an allen key in my electric screwdriver for the AML ones and that is perfect.
I have used the Split Jaw over-fishplate clamps but didn't see any benefit, so stopped using them.