The cold steel from my first post in this thread is particularly nasty, they add black pepper to the mix to induce a sneeze reflex to draw the capsicum deeper into the attacker's mucus membranes.
That wins my vote for best buy!
I've used a ton of pepper spray, practice is important and often over looked.
Get the 2.5 or 3.5 cans because they got the good safety flip over the spray button.
Other kinds where you flick the button to the right, spray in your pocket, from personal experience -
do not carry any pepper spray in front pants pocket !!! Let me tell you - it hurts!
I carried for yrs in San Francisco and got lots of practice, one time as a messenger I checked in a can of grizzly bear at the federal building ( they used to store keys/multi tools etc at the front desk/security) the authoritarian security guard freaked out trying to tell me it was illegal & said he was getting the Fed police ( as if they know CA law-LOL! ) so when I got back to the desk I had a Fed cop waiting there for me, "what do you need this for he asked" I answered ( truthfully ) that I did occasional process serving and sometimes came across angry pitbuls , he then said "you know, you cant use this on people" I remarked "really" it seems to work just fine!" with a cheeky kind of smile. He smiled and handed me the can-the security guard was apoplectic
At one time I was very versed in CA self defense law and weapons laws - I loved people trying to tell me what I cant and couldn't do. ... I'm gonna get some of that cold steel spray for meself