All forms of mechanics that can still be found today can be played well. The underdamping mechanism, which has been standardized since the beginning of the 20th century, is the one that is commonly used today. The Renner company has been one of the best known since the 1920s - and was recently taken over by Steinway & Sons.
In our experience, Ibach and Blüthner Oberdämpfer machine heads from the time until about 1920 are also very good to play. By the way - there was only the underdamping (for example with Erard and Pleyel already before 1850) - after that the upper damping was favoured in Germany because of the better playability and damping, in order to be replaced by the underdamping again later with mechanics parts (above all spring steel) which are better available in the meantime.
There were also different forms of mechanics for the grand piano, which in turn were realized differently by different manufacturers. Roughly speaking, a distinction can be made between the early bounce/impact mechanics (including the so-called "Viennese mechanics"), which did not permit fast repetition and had a more complex damping system, and the later double repetition mechanics based on the inventions of Erard and Hertz (so-called "English mechanics").
In the double repetition mechanism built to this day, the lifting link is moved by a pilot (connection between the end of the key and the mechanism). Some manufacturers have also fixed the connection between the key and the lifting link (abstract mechanics), which allows a higher precision - but is more complicated to renovate and adjust. Although a renovated instrument with a bounce mechanism is of course also nice to play, we would always recommend the modern mechanism form with under-damping for contemporary playing. An exception worth mentioning is the Blüthner patent action, which in good condition allows very easy, controlled and fine playing and also repeats wonderfully for high demands. The success of this type of action is demonstrated by the fact that although Blüthner offered the Blüthner Erard action as early as the 1870s on request, the patent action was increasingly used until the 1920s.
PICTURES OF A WING MECHANISM