Assuming you are creating a good ground (damp feet, wet soil, standing in water, etc.), you can get shocked equally well with either AC or DC. The difference is, AC has the ability to freeze up your muscles, working with DC you go "Ow", and drop whatever hurts. AC you have the very real possiblility of freezing up, and hanging onto the stinger, ground, or whatever.
Under normal circumstances, in a nice dry clean shop, no water, I wouldn't worry about it. But if you're going out, standing hip deep in a manure sump at a dairy or something, DC would be preferable and worth spending the extra money for.
*** Disclaimer ***
As I have no wish to toy with anybody's life, I suggest you take this and all other posts with a certain amount of skepticism. Carefully evaluate, and if necessary, research on your own any suggestions or advice you might pick up here, especially those from my posts, as I obviously haven't the skill and experience exhibited by some of the more illustrious and more successful members of this forum. I'm not responsible for anything I say, as I drank toxic water when young.