I've been using it on guitar cab. I liked it at first but I'm starting to change my mind. There's something kind of grainy with it. It seems to work better on fast attack/quick decay things like drums than a distorted guitar amp.
It could probably stand to shed some highs for cabs. It really has an exceptional high end response for a dynamic, I think that's part of what makes it so good on other things.
As said above, i think the drum tuning is the most important part. Ive only used a 57 on snare and I cant complain. I get a nice crisp snappy sound and still a decent amount of tone.