I should've said calipers. My bad.
The calipers would be the last thing I'd change in the system, but the pads and rotors, absolutely. The difference between stock and j-hook+carbotech is obvious and immediately apparent.
Maybe one day I'll try the upgrade and see for myself. :-)
As far as feel, the RB calipers are advantage as above, but adding the following:
1. The shit dust seals on the stockers. They burn up almost immediately. The RB's require replacement, but keep the pistons nice and clean.
2. Pad changes - driving out the stock brembo pins and screws is a pain. RB's are better.
3. Springs and noise - stocks make more noise.
4. Caliper protection - landing area for pad is protected on RB caliper by replaceable spring. Stock caliper just wears there. Check yours anytime, you'll see.
5. Caliper removal for disc changes - the hard lines for the OEM ones increase the pedal feel, but the flexible lines on the RB one allow you to move the caliper around and get the disc on and off with much less fuss. The number of rotor changes I have done in eight years alone makes this a significant issue.
6. Proper clearance for bigger rotors - the ZR1 rotors and 390mm AP ones I have fit since having my RB's have fit MUCH better in that caliper. I'm convinced that pad cooling and wear has been less due to it.
7. Pad taper - every pad I had on the stock system tapered. Worst on the pagid CCM'. RB's do this much less.