Obviously if your connection isn't very fast it won't be worth paying for. Becouse when you try to kill something you will sit there attacking it and if your lagging or something you won't notice it is actually attacking you back until your dead...
Happens to me all the time so don't say it isn't so. Im on a 56k. too slow.
And yes I try running up to it attacking it and running away as fast as I can... but I still always end up being attacked once or twice... and yet I don't see the damage I got for a few seconds after im away from the creatures...
This would prabably apply to other situations where it's vital for you and the rest of the world to be in sync.... on any server...