Doing pretty well with Logitechs MX Ergo which also looks more polished than this open source alternative.
I am fine with paying for closed source products if they are good and can be used without a hassle.
I love the Ergo. Bought two (in case they stop selling them at some point) and forced my employer to get me one (for H&S reasons). I've been using the pointer finger track ball for years but this feels so much better.
Also it's good for people with big hands.
The only downside is the rubber downside of it. It got unstuck so I had to glue it back onto the metal part. They really didn't think much about that.
afaik they still use cheap switches for the main buttons in those, which lead to problems with the previous model of that line. (mostly the left mouse button failing after 2y). I will still use them, but I am definitely looking for a good alternative with better parts.
Also it's good for people with big hands.
The only downside is the rubber downside of it. It got unstuck so I had to glue it back onto the metal part. They really didn't think much about that.