Well the Shadow and Sovereign are special military. :P But ya I would think so, moreso the latter seeing as they would have at least basic training in using The Force(heightened reflexes/senses, maybe a force power or two) so they could be put on the level of a Sith or at least the average sith warrior, against a true Sith Lord though they could be in trouble.
Against your average rank and file Sith Warrior, the Shadow, Sovereign and Dark Troopers will be fine, but the Sith Lords will prove difficult. I'm thinking the Dark Troopers will be the most effective just because the the sheer firepower they can put out.
Or the AT-AT's can kill the Sith