Former OC and CS instructor here. Been sprayed a few times, and been gassed so many times I can't remember. Can confirm OC is a lot worse than CS. Whereas CS doesn't really hurt, it's just uncomfortable, OC is extremely intense pain(had a former female soldier who claimed it hurt as bad as when she gave birth, although OC is localized, and giving birth is a whole body experience).

A little bit of information;

• CS gas is a psychological gas, wich means if you pass out, you will breathe normally and not be affected by the gas. Also, 1/1000 are immune to CS, along with people who have downs-syndrome, cats and dogs(and probably some more animals).
• If you ever get gassed by accident(this can happen if you are in a city where they use CS-grenades) you should run, do not use water to rinse off, it will burn even worse.
• Do not pick up CS grenades. They burn very hot!
• To distinguish between CS and OC; I always felt CS smelt like marzipan, but not many share my view there. Also, CS comes in the form of white smoke.
• When soldiers get to test the gas, the usually burn some CS-pellets that look like small pills. Depending on the size of the room, usually 2-5 are burned. CS grenades contain the equivalent of 500.
• OC usually comes in either oil-based or water-based versions. I can't remember if I have tried both, but they have the same effect. Only thing is oil lasts forever, and using just water to rinse off is .. futile.
• The usual ways of applying OC is with a stream-spray, or fog-spray. Stream is a long-range(up to 3meters +) thin precision stream(most commonly found on the belt of law enforcement). This is effective to only spray one person without being up in his face. The fog spray has much shorter range, and looks more like a misty fog. This is best used in cases where you panic/uncontrollable environment or there are a lot of targets. For instance I think a lot of self defence sprays are fog, and also riot-control, as seen in the video.
• If you get sprayed by OC, get out of the sun, and rinse heavily with water. Do not use a running stream. Best case is you have two buckets, stick your head in one, get someone to fill the second, when they come back, change buckets, and refill the first bucket. Open your eyes and look around inside the bucket. Keep hair out of your face, particles of OC will stay on the surface of the water, get trapped in your hair as you take your head out of the bucket, and join you in the new bucket(or in the shower later that night).

Lastly, a funny story; We once had sort of a "hell-day" for some soldiers. It was a long day, intense. When the day was coming to an end, I found an excess CS grenade at one of the last posts, and decided to give the squad I was instructor for a little extra. When we were in the middle of no-where, I took the grenade out held it behind my back, pulled the pin and showed it to them. I asked what it was, then said they had 15seconds(NATO standard to get masks on) before I threw the grenade. After 10-12 seconds I threw the grenade. But it malfunctioned, only sipping out a little bit of gas. I decided to rumble the grenade around a bit for it to burn better. I kicked it a bit, this was a mistake... And it "exploded" in the thickest cloud of CS I have ever seen. All my soldiers had masks on, the only one without a mask was me. I had been pestering the soldiers the whole day, and now they got to laugh a bit. It was all good fun. Oh, and the wind blew the way we were going.