The MXR looks like it has lots of useful options. I did look at the MXR with the built in fuzz but it doesn't take a battery which put me off, as when I use this it'll be added to my pedalboard without actually being mounted, sort of like a guest patch-in. The OC2 uses so little battery that it'll work fir a long time before it needs changing, whereas using the MXR I'd have to have a separate adapter or a spare output from my Cioks and a messy loose cable when it's not being used.