I am an OC instructor at my department as a Felony Probation Officer.
We carry Fox Labs just like our Sheriff Department does. We carry the 2oz cans in the stream pattern. It's 2%, 5.3 million SHU. It is non-flammable and has only one opening in the can where it is filled with and where it comes out......some cans used to have the nozzle opening, then an injection hole at the bottom of the can that would become a point of leaks and can failures.
http://www.foxlabs.com/foxlabs.shtml
It is some nasty stuff to say the least......most police and sheriff personnel I have talked to would rather be tazed than deal with this messy, nasty stuff!
I have been sprayed once as a student and once as an instructor in training.
The worst part about this is the inability to open your eyes.....you literally need to hold them open with your fingers to allow water to get in to clean them out. We use baby shampoo and cold water to decontaminate. The soap helps because the oleoresin is an oily substance and soap repels oil as we all know. Typically it takes about 10 minutes before students can keep their eyes open without their hands but I seen some in as little a few minutes and some over 30 minutes.
The other factor with this stuff is it not only irritates, but it also makes mucus membranes swell and if you get enough in your throat and lungs, your breathing can become limited.
It's a frustrating pain/irritant, because the water feels great and you think it's gone till you get away from the water and the exact same pain comes right back! The good thing is it is all natural and will eventually wear off. Our city police officers don't get any water, they just have to let it wear off!
I have probably sprayed a dozen people with it on duty and every time the idiot drops to the ground screaming bloody murder and does exactly what I tell them! But I have heard stories of it not working so well and always keep my guard up. I definitely approach these people with caution when I cuff them cause they can still fight. Lots of felons have had it before, several times, and know what to expect and the "shock" factor is not so great.
Personally, I would stay away from the foam, it's harder to accurately hit the eyes/mouth with it, can't be inhaled as well and even if it does hit, may take several seconds to melt in and affect the eyes, plus, the person can wipe it off and throw it back at you.
Stream would be my choice as Fog may get you a little more and with the stream you can walk it around until it hits the right spot.

Definitely get a holster for it. I carried some in my front pants pocket once and it went off and I noticed my thigh was wet and burning!!! Burned all night too!!

It's good stuff.....just be careful!!!!!