I've been incredibly happy with this: which is apparently called the "Microflate Nano."

It's tiny, weighs barely anything (minus carts, obviously) and has no moving parts. Tighten the cartridge on to break the seal, push onto valve (presta or schraeder), unscrew cartridge slowly until gas starts flowing. Instant 120 psi with a 700x23, although it did take me a couple practice runs before I started seating it properly. I've burned through a 30 pack of cartridges (~$1 apiece) over a few years without a single botched attempt on the road. I slip a piece of inner tube over the cartridge to keep it from freezing to my fingers.

I carry one cartridge and a small Lezyne mini-pump. That way I've got the C02 if I'm lazy or in a hurry, the pump if I want to save CO2, and each is backup if the other fails (or runs out). Plus they're lighter together than either a bigger, faster pump or a safer number of cartridges

I spent $40 three times over on good pumps that got broken, stolen and lost. Probably ruined as many tubes with the frame pumps as I inflated.