How does a CO2 cartridge misfire now? There are CO2 inflators with knobs that allow you to control the flow precisely so you don't dump all the air out all at once.

I think CO2 is the best solution for emergency kit. Now there are specific situations where CO2 does not work- Latex tube, tubular tire (with latex inner) and tubeless sealants. If you don't have those particular setups then CO2 is the best solution.