Be careful re-using yeast from big beers--I've read that you should't re-pitch from anything 1.070 or over.
Also be careful to re-pitch an appropriate amount of slurry--most people would tend to overpitch when re-using slurry. You don't need that much (consult the pitching rate calculator at www.mrmalty.com
for help with how much to re-pitch).
Re-pitching slurry works great if you keep those things in mind. IMO it provides a great source of healthy, viable yeast. I'm not certain, but krausening might be the only better thing out there.