Anyone mess with the electric brake booster set ups?

[Chevy Guy]

I am considering a similar kit. How is the break pedal feel?

I was having persistent issues with my braking system overall, the second gen WS6 systems are notoriously difficult to get feeling "good".

I’ve got the CPP kit. Pedal feel is pretty similar to a newer car. Light, responsive right off the top, lost of power that really ramps up the further you get into the pedal. I had to re-learn how to brake a bit in my Pontiac swapping from a vacuum set up to the ibooster. One thing I did to give me a bit more modulation and to make the brakes a bit less touchy was to drill another hole about an inch above the stock power brake hole on the pedal arm. I found if I mounted the brake pedal clevis in the stock power brake hole it was just a bit too touchy.

Well said, I would describe it as a bit "disconnected", from a driving feel/experience perspective.
My car has much better braking with this set up and I like new technology so I'm pretty happy overall.