Chorewise, spares are more work if you are trimming them. If pre-cut to St. Louis style, you probably still have the membrane to pull. The taste is about the same. Spares are thicker, with more fat and gristle to cook out, but somewhat more meat. They usually take about an hour longer than babybacks. That gives them awhile longer to pick up some extra smoke.

Actually, I would tend to disagree a bit with regards to flavor. The spares come from right on top of the belly, from whence magical, glorious bacon comes. I think that the spares have better flavor and they need to cook longer -- meaning more smoke flavor, which I like. I don't turn my nore up at baby backs by any means, but I prefer St. Louis cut spares any day of the week.