Buttkicker transducer vs earthquake transducer vs ???


Hey guys, 

Wondering what you guys use for seat transducers and what luck you have had with them.  I currently have buttkickers but they seem spotty at best.  I just experienced earthquakes transducers in a demo.  It was great and seemed steady. Has anyone else used them and have they worked well for you? What amp do you use with them and what size transducer? I see that earthquake has two different models, a small and a large. 
mgould
The key once again is to use not just one but several. I like to combine metamucil with prune juice. Earthquake! Buttkicker!!!
Ouch.  If you are looking for a more visceral experience, see if you can find a used HSU MBM-12 (mid-bass module).  I only use mine when watching movies.  I have it positioned right behind my sofa and it gives you more of that feel of being there.
Where can I get one?  I have been looking for an MBM-12 for a while.