speaking in terms of pure effectiveness, I would choose a GOOD QUALITY pepper foam and the largest legal folder I could carry, gives you a couple of different levels of defense. biggest consideration with pepper spray is it has pretty poor performance in the cold. Once snow hits, is when most of us at work go to get certified in the use of OC/Pepper spray due to the fact that it doesn't hurt as bad when we get sprayed.
As an interesting footnote, it was once mentioned by Massad Ayoob that it's legal to carry a MagLite in all fifty states, regardless of size. uhmmm...not that I'd carry one of those things with me 24/7 but there nice to keep in a nearby bag, or in a a car, etc. Speaking of flashlights, I've recently learned the wonderful results one can acquire by using a "Stylus LED light" like a Yawara stick, Amazing how compliant a combative person could become when encouraged by a bit of noxious stimuli.
or at least these are my perceptions, I may be one of the least qualified opinions in these forums on this matter due to that fact that I still live in a VERY conservative state regarding weapons laws etc. good luck to ya'!