150 wpf is good. 170 is even better. It is worth it if you can get it without making too many sacrifices.
WPF increases swing speed (faster) and adds a bit of damage. I've heard people say that more than 130 wpf is pretty good for a main weapon. If you have 150 you will be pretty darn fast and good to go. Having 170 is like expert and you will swing even faster. Still, even if you are really fast it doesn't mean you'll p0wn''d everyone. Footwork and blocking skill is very important. Some people that top the charts only have 100 wpf in their weapons kill, but still kick ass because they have good timing and footwork.
There aren't any charts as far as I know. Since its an indy mod, a lot of things are unofficial and up to the users to discover. If you do some searching on the forum you might find a thread with a comparison for different swing speeds and wpf skill. If I find it I will post the link here.