I thought the dots were rough matching of output levels?
Nick - you are going to have to do some serious reading, because they are very different. Apart from anything else, as Cavedog101 implies, the B1s have a very wide cardioid pattern, which may or may not be preferable depending on your uses. I would have no qualms using my B3 (or a pair of them) for a jazz kit, but I might want something a little tighter for rock, aiming to get better seperation.
That said, my drum recordings suck ass IMO, so I'm no expert!!