I am trying to find out the main differences between these two types of forums. I am familiar with vbulletin from using it, but am looking for a way to create a forum that is very secure. I want to determine who can visit it and keep the content from being available to the public. I also need to make it look like the site that it will be attached to. Any advice is helpful.

Also, i see vbulletin used in a lot of places and they all look the same. I'm wondering if this is because users don't have much control over what the site looks like??

Mary