I researched pumps after a failed roadside flat repair with CO2. CO2 is fine until you run out of cartridges for whatever reason. I suppose you could carry a bunch of cartridges, but even then when you are unfortunate enough to have that really bad day when you encounter more than one flat, you pretty much run out of luck. Besides the weight and bulk of multiple cartridges is not really worth the bother.

Now I pack a Lezyne Road Drive. Don’t need CO2 anymore. I settled on this pump because of small size, low weight (actually lighter than two CO2 cartridges and head), connection via small hose that stores inside, dust caps that stay in place, and I can pump up to my regular tire pressures. Also, the price was right. It does take 200 strokes or so, but it never runs out of air.