The rotella 15w40 is ok if you change your oil every ride or couple of hours. Otherwise it begins to breakdown.
The consensus in this forum is the motorcycle specific Mobil 1, Maxima
or amsoil synthetics are the ones to use. Amsoil can be had for 1/2 the price you see at Canadian tire if you buy their membership, so it's the one I use. Shipping isn't bad if you buy online, but I found a local "dealer" who stocked boxes of it in my city. Maybe you can find the same thing.
Edit: Forgot to add, since you can safely run the amsoil 2-3 times longer than the rotella, the cost savings isn't really there to use the cheap oil.
Edited by cereal killer, March 25, 2013 - 04:14 PM.