I always wanted to make a baittube, but never got around to it. Last week while cleaning up the garage, I finally threw the pipes and caps away.
My logic was that the tube is a great alternative to external bait tank I used to have. It probably adds some drag but I didn't think it would be a significant factor, but that is subject to any individual's tolerance level. I now have a kayatank which is always there, so I don't see a tube in my future.
Masta's post that started the tube craze:
http://www.bigwatersedge.com/bwevb/showthread.php?t=5