I've been dying to try a Goatkeeper myself, but they're pretty rare and I've never seen one up for sale.
There's another bizarre trem I found on HC called the Hollow Earth that's worth checking out. It's a pretty mind blowing DIY build, and the builder is considering going into production. Here's a link:
Link Removed
I have a Hummingbird, which is similar to the Valcoder. It's very limited, but sounds really good at the one thing it does well--hard chop.
I just built a BYOC Tremster, based on the old EA circuit, and it sounds very sweet and organic. This one has a broad speed range and I don't notice any low end loss. There's a trim pot inside to cure the volume drop, but too much gain introduces some hiss.
Anyway, not sure what my point is here... just know that there's tons of trems to try out.