I just don't see the CO2 being that much faster. I used to bring a couple of CO2 cartridges and their delivery system/valve but I realized that the volume was actually about the same as the road morph (albeit easier to pack because it's broken up into pieces), and the weight's within 100 grams or so.

I do tend to flub the CO2 seal too. The pumping itself probably adds about 2 minutes over the cartridges, some of which is recouped by the fact I don't have to assemble the cartridges.

I just carry the pump in the (messenger) bag as I have to lock the bike up outside anyway and I don't want to leave it on there.