Thanks everyone, after listening to advice here and watching some YouTube videos I'm still in a quandary as to what to get them.
1) stun gun: up close and it appears you need prolonged contact to do much more than give them a zap and piss them off.
2) taser: better range, but you have to hit your mark, larger than a stun gun, doubt I could get them to carry it all the time. Also worry at first sight may be mistaken as a pistol and get them shot.
3) pepper spray: getting the spray blown back into their face or breathing it in if in the heat of the moment if they spray into the wind.
As an authorized TASER dealer I may be a little biased, but I would go for the Pulse. Very compact, you can actually cover it with your hand, concealed carry is GTG, and it has an integral laser for getting that shot off accurately. It can also be used as a stun gun without the prong cartridge if desired.
Best choice would be a combination of TASER and OC spray.
And yes, TASERS are legal in MD with the exception of Ocean City. Recent lawsuits have resulted in laws being changed.
I have the Pulse in stock if you are interested.