With the more modern stuff available....I wouldn't run the 4 piston calipers if my life depended on it. There's a lot better stuff out there if you're not going for a restoration. Even the 73-76 single piston stuff is way better.
The factory four-piston calipers work great, as long as the car is used regularly, and the pistons do not hang up in the bores, due to corrosion/pitting in the bores. Rebuilding these calipers is very straight-forward, and can be accomplished with very simple hand tools.
A re-sleeving service is available that fits new stainless steel sleeves into the bores, and that takes care of any future bore issues.
Take a look at any of the modern supercars including Viper, Corvette ZR1, Buggati Veyron, even the Challenger SRT8; all use multiple piston calipers.
The '73-'76 calipers use a single piston caliper design.