Like most people I rarely preach about good experiences but will be vocal about bad ones, but I'm going to make an exception for The Guitammer Company (Butticker's parent company). It's a long read, but I hope you guys read it and see how a company should be run.
I did a lot of reading about Buttkickers but was dismayed when I actually tried to find one to purchase. It seems they can't make enough of them as it looks like they've had trouble keeping stock for the past few years. Out of desperation I bought a second hand Buttkicker Advance Kit off of ebay. When it arrived I hooked it up and immediately noticed the dreaded knocking/rattling sound at higher volumes. Over time it because so bad it was knocking at almost any volume. I noticed that the Buttkicker LFE transducers were finally available again, so I just took my loss on the Advance transducer and purchased the LFE. Just out of curiosity I emailed customer support at Buttkicker to ask if there was anything I can do for my broken Advance. Surprisingly they told me they'd ship out a new one even though I made it clear I bought it second hand!
Now I saw that the LFE kit was in stock at certain retailers, and since I had the extra LFE and a huge reclining sectional, I pulled the trigger on the LFE kit. The LFE kit came in and unfortunately the amp was DOA. I emailed customer support again and once again they shipped a replacement out asap! So now I'm rocking dual LFE's on the 1000W amp, and an Advance on the 300w amp and it's beyond awesome.
I'm not going to bore you with the performance of the buttkickers as that's already well documented on this site. But their customer support is beyond exemplary, and easily the best I've ever seen. No hoops to jump through, no phone tag, nothing. They sent me two replacement products, with prepaid return shipping labels, without asking for a single serial, invoice or even a credit card number. Email correspondence with them is lightning fast. I asked Andrew a question and he responded with a lengthy reply faster than I could type the initial question (under 3 minutes). I've been in customer service for nearly half my life, and I've yet to see a company run the way these guys do. They really do care about their customers.