With plates/lifters you can power into a turn more, and I think it may help to hold an edge for longer too, but flat-mounted bindings are better when it comes to park/pow cause plates make it difficult to land and ski pow, because plates are mainly designed for carvers and they need the pow in the toe, so you'll find a lot of your weight is over the front of the ski whih makes it dificult for pow.
Dunno, I might be wrong. But flat bindings are definitely better for park/pow, I might just have the details wrong.