Originally Posted by phughes

It all depends on your bike and what you feel comfortable carrying. For me, the Road Morph carries easily. It is attached to the rear of the seat tube between it and the rear tire. It is a no brainer on this bike and it has seen a lot of use. I don't have to put it in my bag. Co2 inflators work, but I am more comfortable with a pump since it doesn't need to be replenished. If I got two flats, no problem. Thankfully I haven't had many flats. I just went over 2,000 miles with no flats, then had two in a month. The nice think about the pump was that I could put in a little air, ride a short distance, then change it where it was safer. I then still had a way to pump up the tire.

C02 is a great little option for those who don't want, or cannot carry a pump for some reason. I consider them a second choice for me though.