You can look it up at the MSD site also. Since I have never used one and haven't felt the benefits myself, I copied this over from the MSD site.
These capacitive discharge Ignitions feature multi-channel capability complemented with multiple sparks, rev limiters and a timing control.
The new DIS Ignitions are engineered with the latest in digital science including power MOSFET technology and efficient IGBT coil drivers. The features of the ignitions are managed by a 15 MHz microcontroller for extremely fast compensations and decisions. In the end this creates incredibly accurate spark delivery, rev limit and timing functions.
The multi-channel design of the MSD DIS Ignitions saturate each coil pack with 470 volts and up to 115 millijoules of spark energy. This creates more efficient combustion in the cylinders to produce more power. Throttle response and mid range pull are also improved due to a series of powerful multiple sparks that last for 20° of crankshaft rotation.
To complete the package MSD engineers built several great programmable features into the DIS ignitions to give you better performance on the track. There is a Two Step Rev Control which gives you one limit to set for holeshots and another for top end performance. For engines using nitrous or extremely high cylinder pressures you can also program a High Speed Retard after the engine hits total timing. Both of these features are easy to adjust with built-in dip switches.
With proven MSD Ignition technology and years of performance ignition experience, an MSD DIS will make a great addition to your car!
Switch between two rev limits that adjust with rotary switches in 100 rpm increments.>>>>I know this will allow you to set two different rev limiters for yourself. If you are launching you can have the pedal all the way to the floor but you will not go over what you set it at. i.e 4300 rpms. You can also set your top end rev to never go above 6600 rpms or whatever you would like yourself at.
Single stage retard for nitrous and top end performance.
Start retard eases pressure on the starter, flywheel and engine.
Adjustable magnetic pickup compensation produces accurate trigger signals.
LED display warns of trigger signal problems or faulty charging system.
Fully potted with polyurethane for vibration and water protection.
>>>Like I said though, I have not used it myself so I can't vouch for it. I can say that it is brand new and in the box.
I hope this helps.