For the first 6 or 7 years I played I played with a fairly poor 28K dial-up connection, that generally hovered right around 250ms ping time.
I then upgraded (er, the internet came to my house in the sticks) and now have a much faster connection with pings in the 65-75 range.
When I made the connection transition I was unable to discern any difference in game-play, or shooting, or timing of any sort.
At one point in there (with my old connection) I made a substantial computer upgrade. I noticed a massive change to game-play and shooting at that point (everything got much easier).