From the "any exercise is better than no exercise" perspective, I'd imagine that playing drums at high tempo would be considered effective - it certainly can work up a sweat and obviously must burn more calories than just sitting on the couch, but it's hard to say how effective it actually is without hard numbers. Are there any reliable sources which can provide MET or actual calorie burn data by which we could compare drumming with other exercises?
Also, while it's obviously physically taxing beyond a certain level of skill, does drumming actually raise the heart rate enough to really count as cardio?