I've always thought a post with negative comments was the most helpful. When I see a list of good and bad things about a place it gives me better insight. Often, what someone else sees as a negative (say, loud music all night) I might see as a positive, or at least not important to me. I'll just bring ear-plugs.
So please, post negative things. It helps me to know what to pack (i.e. Lysol for the AC, poor WiFi), and lets me know what to expect.
Fort a good example of messed up TA posts see the hotel listings around Salt Lake City. There was a posting war between ski resorts that was so over the top it put me off a trip out there. If the operators were so willing to slander each other, why should I trust any of them?