I've used the bullheads for the last two seasons and took 4 turkeys with them in that time. They are tougher than the guillotines, that's for sure, and just as effective.
We've learned the way to practice with them over and over without ruining the blades is to pen a paper target over the top of some 4" foam, with your regular target behind the foam. The broadheads will punch the paper and bounce off of the foam without ruining the blades.
I will be using the bullheads again this year. Just love the fact that I don't have to track my turkeys down after I shoot'em.