And as mechanical keyboards became more mainstream, keyboard discussions migrated from this niche place to mainstream forums.
You will find more discussions on forums that cater to PC gaming these days: now that all the PC gamers have mechanical keyboards they don't switch to another forum just to talk about them.

I do think that the oldtimers who once built this hobby* do check in here now and then. They won't be visiting every PC gaming site.

Unfortunately, Geekhack also has a problem with spambots. I report several every day, and the mods do a heroic job of removing them, but they keep coming and dilute the quality of the forum.

*:  whatever "the hobby" is ...which is different for everyone.

The most similar ones I can think of would be the Gameball or Kensington Orbit.

Other finger balls that you might want to consider could be Elecom's Huge or Deft Pro, Kensington's Expert and the L-Trac.

I finally got my hands on the HMX Anti switch and, honestly, it’s a wild ride. At first, the scratchiness threw me off a bit, but after a few hours of typing, I started to appreciate the tactile unpredictability—it’s unlike any HMX switch I’ve used before.

The stem wobble is definitely noticeable, but in a strangely satisfying way; it gives each keypress a kind of “alive” feel that I haven’t experienced in most modern switches. It’s not for everyone, especially if you prefer smooth, linear action, but for someone looking for a unique typing experience, it’s a lot of fun.

I also ran it through some of my own typing tests and the force curve feels quirky but interesting—the bottom-out is a little heavier than expected, and the reset is pretty quick. Overall, I’d give it a solid 7.5/10 for novelty and character. Definitely a switch to try if you’re curious about something completely different.

I adore this set, but after ordering and realizing to get the normal 2 with @ I needed to order the extension I was pretty unhappy. Even more unhappy to find the alt alphas have no way of getting a normal 2 with @.