I PvP-ed with 120-150 ping during 90% of my pvp career. So I'd say that kind of ping is enough for fine PvP experience. But having 100 ping or less, or even sub 80, seriously, that feels like you are the host, and not someone else. Best host I ever experienced was FoE hosting via hamachi, had like 100 ping most and I felt like a king on it.