ButtKickers. Experience Anyone?

I'm considering adding a Buttkicker shaker to my HT. If I decide to do this, It will be mounted under a LA-Z-Boy double recliner sofa, & I suppose mated with a 1000W Carvin amp since thats what the manufacturer recommends. I can get the Buttkicker & the amp as a pair for $799.00 plus free shipping. What do you know about these? Anyone? Thanks, Phil Griffin..