Currently building a Super Big Bertha with plans to launch with on Estes E12 black powder engines. These engines are cheap (E12-4 cost $6) and readily available locally. But reading through the Rocketry Forum I came across the CATO list. The list was full of E12 black powder engines. Now I don't know if my original plans were misguided. I wanted a nice slow dramatic (affordable) launch on a 13 ounce rocket and the E12 was a good match. But are E12s reliable? Are they on the CATO list because more people can afford to use them, or because they are more likely to CATO?
https://www.rocketryforum.com/threads/suspected-bad-motor-list.150501/
https://www.rocketryforum.com/threads/suspected-bad-motor-list.150501/