Steve,
The CI grates on the Smokey Joe do get really hot so I use less charcoal than before. I tend to bank the coals to one side when grilling chicken but using direct heat, you get some great sear marks on steaks and burgers. I actually purchased a grill/griddle grate from Craycort for the SJ, but I have only used it once. The regular grates do everything that I need.
Comparing the CI grates on the 22.5" and the SJ, the results are similar because of the amounts of charcoal and adjustable vents. Even with a greater distance in height on the 22.5", you can get it really hot, comparable to the SJ. Bottom line: they are both a big improvement over the standard Weber grates. One thing about the CI grates on the SJ: check the wing nuts on the legs regularly. The weight of the grates seems to require you to tighten the legs frequently.
Hope this helped!
Dan