SortaleFrom my experience, Steam version is significantly slower in both Main menu loading times and game session loading times. It also very annoyingly places Spring folder deep into Steam intestines, and I like all my games to be nicely piled together in C:/Games. Add to this constant memory hogging by Steam's overlay app.
So no, Steam is bad. Though, there is one issue in original version as well: in my case, all unit names and short descriptios are in Russian, and I would like my game to be entirely in English. Is there a way I can change that?