I have been applying 139 park brake for almost 5 years now, for most of that on my own and latterly with both pilots together to share the load (and avoid the chance of your foot slipping and putting in an abrupt pedal input)
Either way I have not heard people complaining about it, wheras they did all the time about the original seat types with the side bars that dig in.
Personally I don't see a problem with the brake
Regards CF