Curious to know what is the difference between Quantums Infinite ACS compared to magnetic and centrifugal brakes that other reels use.

I have it on my Energys and like it. I also have several of the old green curados.

Both systems are good. I've setup my curados once and haven't need to change them since. I do find that I play more with the ACS system.

Personally I like the ACS system better. I generally keep everything set really loose. Come a windy day I can really fine tune it and get it just how I like it. Make dialing it in pretty easy.

I don't think you can go wrong with eother type of system.

This is one area that Quantum really shines. They aren't the only ones BUT they have external centrifugal braking control. You don't have to take the sideplate off to adjust the beads. You just turn the dial from free spool to 3,6, or 9. Great system!

Now, you can do this with magnetic braking but I haven't ever liked that system as much as centrifugal.

The difference between Quantum's ACS and Infinite ACS is the number of brakes that are applied. Both of the systems are adjustable by a dial without having to remove the sideplate. With each turn of the dial the brake race is moved in or out to allow the brakes to contact the race, therefore applying that brake or brake set. On the regular ACS, you get either free(0 brakes), 3, 6, or 9(full on). With the Infinite ACS, you go in 1 brake increments from 0 to 9. Like bassdocktor said, the Infinite system offers more fine tuning which helps on those windy days.