Not a Thudbuster but I used to have one before replacing it with this so I can provide even more info. 🫠 It's a Kinekt. I liked the Thudbuster and wouldn't ride without it. My back pain disappeared. That said the Kinekt is better. Specifically because there's a preload adjustment. The Thudbuster is either bouncy during normal riding or stiffer than you need it due to the nature of its adjustability. You put a different elastomer, each covering a range of weights. It's fine and it works, but the Kinekt allows for precise adjustment via preload to eliminate bounciness during normal riding. I think the Suntour NCX might be even better and it's cheaper if you don't care about its weight.

I don't recall where I got them from anymore. I think I've had them for a decade now. 😂