PP mode loses a little dynamics and smoothness vs SE mode, but it adds focus, detail, and texture, particularly in the higher frequencies. The loss in dynamics doesn't matter for classical, which is already dynamic af, and the extra detail/texture makes horns and strings sound more real, especially in the upper registers. I also feel like maybe there's a very slight bass roll-off for PP vs SE with less slam? But that could also just be the loss of dynamics.
Just switched from classical ("Mythologies" by Anna Clyne) to "Awaken, My Love!" by Childish Gambino and I definitely prefer the dynamics/slam and smoothness of SE mode, but PP is really, really good for classical.