I enjoyed this video (watch out for non-family language). It brought back memories of when I was in grad school and working as a private security officer. We were made to qualify with OC (oleoresin capsicum) with the same training folks the Sheriff's office used, part of which involved being sprayed.
This video really demonstrated one important point very well:
OC spray is a strong irritant, but is not debilitating in most cases. This girl ran a (simple) obstacle course and performed fairly well in physical combat skills even after taking a goodly dose full-on.
When we were taking the SO's OC ccourse they highlighted some studies that had been done with OC. The researchers would spray a participant and have them navigate an obstacle course (around folding tables, etc...) with the goal of touching the sprayer before having to be washed off. 100% of particiants were able to find, catch, and touch the sprayer (who was told to evade at a walking pace), regardless of age, gender, etc...
The moral of this story: If you are considering OC spray as a self-defense, please reconsider.