I'd be curious how many folks here have done this.
I was an EMT for all of college, and although this was a long time ago, I never once used one even on 911/fire calls. Never intubated. Never used the defib.
These are some exotic toys we're talking about for a first aid kit. Difficult for me to get excited about this kind of thing when I didn't get to use them even when I wanted to do so.
At this point, I don't even have a CPR card anymore, though.