The Buttkicker website has links to some professional reviews:http://thebuttkicker.com/reviews/index.htm
I've used one of the original Buttkicker shakers for about 10 years. They don't make that particular model anymore but it's basically a larger version of the Buttkicker LFE. In addition to my subs, my receiver's LFE output goes to a Buttkicker BKA1000 amp, then to the shaker which is attached to the floor joists under my couch. (There's a crawl space under my theater room.) The amp passes frequencies under 60 Hz to the shaker.
If you enjoy action flicks a shaker can add to the realism. My favorite shaker movie is "Contact". When Ellie (Jodie Foster) rides the capsule through the wormhole the Buttkicker energizes the whole room. Feeling the vibrations in your feet & buns while viewing the violent shaking of the capsule makes you feel like you're in there with her. Movies with "exploding things" have more impact. I think you'd find a shaker to be a fun enhancement to your home theater.