My wife and I just replaced one of our (30 year old) American Standard toilets with a new American Standard Cadet 3 a few months ago, and it works perfectly. Being a new model, it is one of the 1.6 gallon units, and it flushes extremely fast and efficiently. We looked at the American Standard Champion before purchasing the Cadet, and at the time we didn't know of the complaints about the Champion model. We just went with the Cadet 3 because it was less expensive and looked fine. Now that we've read about the Champion problems, we're glad that we went with the Cadet 3. I can only assume that American Standard didn't do enough design work when they came out with the new Champion model, but the Cadet 3 is an excellent unit. Unlike the Champion model, which uses a new flush system, the Cadet 3 uses the same tried and true system that our old and very reliable American Standard toilet used. Of course, it's even better than our old unit, since it's the 1.6 gallon type. The Cadet 3 flushes so fast and quietly that we were amazed at its efficiency.
Incidentally, we bought the standard height model (not the "right height" model), but I don't believe that there would be any difference in performance between the two.