I used self-sealing tubes for a few years. At first I thought they were pretty great, but I eventually gave up. The problems I encountered were:

--can't run very high pressure
--sealant dries in the valve so you can't inflate the tire
--sealant is messy stuff when it gets out (especially when it gets into the pump, as already noted)
--sealant prevents regular patches from sticking, even when there isn't enough of it to seal a puncture

I carry a patch kit and pump and an extra tube that I only deploy if I can't patch the puncture right away. I'll usually pull the tube out of the tire and patch it without bothering to remove the wheel. Patching tubes is a skill worth maintaining. Get out of practice, and you'll be in trouble!