No experience with BetterMouse so I can't say, but I've used SteerMouse for like 10 years with a variety of mice (currently a MX Master 3) and love it. Extremely stable, well written, and powerful. The few times I've had a question, the developer (who is based in Japan) has responded promptly.
The only thing I'd say is given it allows you to customize everything a mouse does in a huge number of ways, it has a bit of a learning curve (as any powerful, full-featured software does). But the UI is well-considered and you can be up and running with it quickly. It's easy to adjust one aspect of your mouse's performance at a time without much risk.