I did it... I think that it's faster than a warp, because a warp takes time to, well, warp you, and make the weird sound. The suckertube will take you all the way to the top of the lvl, directly above the suckertube, and if there is a tile at the very top, you're stuck. It also doesn't matter if it's an X-speed or a Y-speed. You will also stay rolling for a very long time. Pretty cool.