I think this is a good system.
In fact i am one of the ones who reccomended it.
I am part of another forum who is very large and uses same system.
they have 75,000 members compared to our 16,000
I think if you have a good valid reason to leave someone a neg rep and do so.
Probally a good thing to do is in a nice way explain what they were wrong on..
In the rep comment