I'm in the "both" camp. I just began taking CO2 on rides a couple of years ago. I've been cycling for 40 years and can't believe I was a holdout for so long. The first flat I had and used CO2 I thougth back to all those flats over the years where pumped and pumped and pumped to get up to 100psi. The CO2 gets it up to that in seconds. But a piece of advice, in case no one else mentioned it...make sure that you practice at home with your inflater before you have to use it for a real flat.
Dan