I have the kit without e brake on my k2500, which has the semi float axle.
Cons:
-I had to pull the axles out and grind a small amount of casting flash off of the inside of both axles to allow the rotors to sit flat.
-The brackets that hold the brake calipers aren't perfect. They hold the caliper a little too far away from the rotor so the furthest away (from the rotor) part of the brake pad doesn't make contact with the rotor. The brackets are also a little crooked. If doing this again, I would have tried to bend the brackets (so the calipers mount straight on the rotors) before calling the install done.
Pros:
-Checking and changing pads is easy and quick.
-The semi float 14 bolt relies on clips (similar to the 10 bolt) to hold the axles in - with the disc kit installed, the rotor will keep your axle in place if the clip fails.
It has been a while since I bought my kit. Hopefully they have improved by now. GM's manufacturing tolerances/practices seemed to be a bit unpredictable during the time that these trucks were built. The majority of the aftermarket company's parts that I have purchased required a welder and grinder to make them work right - add that all together and it might be a project...
I don't know if these discs are better than drums, as my oem rear brakes were bad when I bought the truck.
I don't know how your front to rear proportioning will work because I removed my abs and added a wilwood adjustable proportioning valve at the same time as the disc kit.