I used the guillotines before the bullheads came out. We use longer arrows and instead of blazer vanes, we put 5" feathers on. I think your rig really needs to be tuned to get the arrow flying as true as possible with either broadhead because they both have a lot of blade out front, and if they don't get launched perfectly straight, those blades out front will make'em fly goofy.
The bullhead blades are definately tougher than the guillotines, but we found that shooting them into some 4" foam over a block target, with a simple home made paper target pinned on the foam, that the arrow will bounce off and not damage the blades. This way, you can shoot'em over and over.