We were assigned Dressler, and I didn't read beyond the assignments, so I can't speak to its usefulness as a supplement...but it was decent for actual course reading.
Our exam format was short answer, AND open book/note -- and the exam was designed so you actually needed your book and notes (i.e. look up this WI statute we didn't ever study, analyze it using the canons we did study, then compare it to the MPC equivalent that we also didn't study).Supplements would have been useless. Your mileage, of course, may vary.