I bought mine from my local bike shop, I felt like a fool when I found it here for $30 less. These guys have the best price.
On to the review, this is the best comfort bike upgrade I've ever bought. Better than a cushy seat or a cheaper suspension seatpost. I ride mostly in the city, so I'm hitting potholes and curbs all the time, and this thing just soaks up the impacts. I can now ride about 5 mph faster, and more comfortably than ever before because I don't feel like I'm sitting on a jackhammer anymore. I feel more in control when I'm not bouncing off of my seat. I will note, my Thudbuster came with two level 5 (medium) elastomers, which was too stiff for me. I had to switch to the level 3 (soft) elastomers to get maximum comfort. If you're a skinny 140-pound college kid like me, you probably need different elastomers. I highly recommend the Thudbuster, it makes the bumpiest road seem butter smooth.