If you bought Marshall DSL40CR you are probably happy with features. Actually, you need nothing more to make great performance. Anyway, more equipment are very useful. You can reach almost all you need with supported foots witch, but with this one every button has one operation and you can easily choose clean, crunch, OV1, OV2, Master 1 or 2 and turn off/turn on FX.
So esspecially if you use FX (and FX makes difference) this pedal is must have.
Pros:
Easy handling (Footing?)
Strong construction.
Nice design
Equipped cable is long enough to make space for other equipment.
Cons:
Big price
It is compatibile only with one amplifier for now.