Both blu and Volcano sell the same product (the JSB L88b), just branded with different logos, different colored LEDs, etc. But all the stuff is interchangeable (though they won't tell you that). The carts should be identical.
That said, I will note that I've bought 401 carts from three different vendors and they've all been different in small ways, so I suppose there's always a chance of slight variations. Nothing that should affect their usage, though.
