I think it's fair to say that as long as you've got a reasonably fresh Energiser 9V battery in here you'll be okay (third party batteries are hit and miss - it's not worth the time finding out). Should you satisfy it with your battery offering then it'll light off A, B and C class motors without trouble but replace it as soon as you can with something more reliable (the 4xAA launcher from Estes is a big improvement) or mod it to take a better battery.
Ultimately, like the lightsaber in Star Wars, you're best off building your own - it's a rite of passage.
Editor's note: The two pre-mature launch incidents I have witnessed both involved home brew launch controllers. Estes is bringing back the 4xAA controller (hurrah). The Klima one can optionally take two 9V PP3s while the Estes Pro Series II controller takes a bunch of C cells and has two sets of launch clips.Rating: [2 of 5 Stars!]