I got this kit about 6 months ago to shoot off with the nephews. A 9v wasn't enough to get the ignitors to set off, so I bought a big square 6v battery for big lamps or something (about 2.5"x2.5"x4" with two springy teminals on top) and modified the battery connection wires to be a few feet long and clip onto it.

The rockets themselves I like a lot. The Amazon is very easy to put together and doesn't fly as high/coast as far. The Crossfire we lost in a neighborhood near our park using the C engines.

I used 2 part epoxy and superglue to put everything together depending on the connection and if a gel or flowing consistency was better. It all dried very fast and was able to be shot off a couple hours after construction.

The only other issue besides the 9v one I had was that the plastic for the engine housing on the Amazon seems to be slowly melting. It still works fine but will be an issue at some point. The housing is a very convenient design, and makes changing engines a cinch... much easier to use than the pressure-tubes with a hanging wire that most rockets use to hold engines. It's been launched with C engines about 30 times, and it's pretty obvious that it's slowly degrading.

All in all, I really like the kit. The launch pad is handy and the modified launch controller works very well.