I played on a Yamaha upright at school I was visiting recently. I noticed it couldn't do repeated notes quiet as fast as I would have liked. Maybe it was just that piano, but even some keyboard repeat faster than that one.In terms of brans in general, are there some brands that are better for repetition?
The trick with an upright is to regulate it with closer checking by catching the hammer closer to the strings as it rebounds. That allows the jack to reset before the key is fully raised. Probably not so easy with a worn action.If a piano has a "jack slap" rail it's possible to regulate it so the jack resets about half way, so I understand. These rails are common in European pianos, not so common in American pianos - not sure about Kawai, Yamaha, etc.