People really have issues pressing any of the L/R buttons? All six are the most ergonomic buttons on the controller.
They're really not. L3 and R3 (particularly R3 because I'm a right-handed trackball user) have really started to hurt my hands in the last couple of years. They're easy to reach, but I would not call them ergonomic by any measure. Being able to move the run and melee buttons somewhere else is fantastic.
A strange effect of the back button attachment is that it slightly tilts my hand position forward, which makes the reach to L1/R2 a little more difficult and kind of makes me want to move L2/R2 down to the back buttons.
I really hope they go back toward the palm grips of the older Dual Shocks for DS5, because the more finger-oriented grips of DS4 are a little wonky when you can no longer hold onto them with your middle finger.
Overall, really nice addon. I'd recommend it to anyone who wants back buttons or doesn't like clicking sticks. Really, the worst thing about it is that the button action feels so much better than the standard buttons that it makes me wish they had a front button attachment too.