For something like a pump that I may never actually use and will easily forget about until I need it, I prefer something completely manual and reliable that requires no batteries to charge. Chances are that if I had a battery powered pump, the battery would be dead on the day I had to use it. I also ditched CO2 for a manual mini pump as I was on a ride where I got more than 2 flats and only had 2 CO2 cartridges. With the modern trend towards wider tires and much lower tire pressures, getting a tire up to 60 PSI, even with a manual mini pump, isn't that hard... even for the scrawniest of bicyclists.
