Haven't thought about a budget, just want a good one.
I made my own for about $45 and works great! I really would say that the Diamond one is the best, I just didn’t want to drop $500 on it.
I have had a Ballstar for the past 20 years.....works great and nary any problems whatsoever.
I have a friend that's had a ballstar cleaner for a long time and he loves it. He told me the older ballstars are better than the newer ballstars.
It seems everything was made better back when...more metal, less plastic. Bigger, more powerful motors that would last a life time. Nowadays, not so much, but they cost more....funny how that works.
One that does NOT wear the outer ball surface. If you cleaning one ball set. Use your hands and just clean water.
For my standards, my bucket polisher works great.
I'd hand polish before I spent $500.
Yes - stick with a polisher ( like the Diamond) that separates the balls as they rotate. It cannot be good in the long run for the balls to rotate and rub against each other as they are cleaned (as in most homemade bucket polishers) . That will inevitably lead to wear that reduces the ball diameters.