I did a lot of PvP today without the Chloranthy Ring +2. It didn't really seem to make a difference, at least for me. I have 38 endurance + Third Dragon Ring, so I have 155 stamina, and nobody is aggressive enough to get me to lose my stamina entirely. It's sometimes close, but not enough. If you have lower stamina it might help, but otherwise...
Right now I have Ring of Life/Soul Protection, Ring of Blades +2, Third Dragon Ring, and then I decided to put Life Ring on, which gives me 200 or more HP, because nothing else seemed that great. Old Sun Ring I find is easily avoidable, and it's helped me a bit in some battles, but I just went for more HP. I have 2200+ HP with 45 Vig, Third Dragon Ring, and Life Ring.
Managed to win most of my battles.