"Positive energy is integrative, holistic, all-inclusive and unconditional. Negative energy on the other hand, segregates, disallows, and is highly conditional." - Bashar
If you want your brand to be accepted as "One of Us", then be open about it. People only trash talk your brand because you deserve it. If your brand delivers on its promises, they will shower it with praise, and will even defend it against negative comments.
Take a look at Facebook pages that are in broadcast-only mode. These are usually brands that people complain about. They do not allow their audience to freely post on their wall for fear of negative feedback.
The page reads like everything is orchestrated. It gets so boring in there that even the moderators barely check-in on the page anymore. You start wondering--if thousands liked this page, where are the conversations?
People know what BS is, and can smell it from a mile away. They can tell if your page only allows the good to come out about your brand. That's not being honest, don't you agree?
If you are thinking of getting a facebook fan page for your brand, first decide how you are going to deal with negative comment. Are you going to delete them, or use them as the fertilizer that it is and use it for positive growth?
Flows like the river
If a brand were sincere about its promises, they will open up their facebook walls. These brands will listen to what people are saying about it, then start making positive changes. Use negative feedback about your brand to improve. Over time, you will convert these neggies into advocates for your brand.
As much as possible, do not moderate the group. Instead let the fans moderate the conversations. Your job is to listen and facilitate. Would you rather have them trash talk about you behind your back? Or would you rather be in on the conversation so you can do something about it?