There are some very good documentaions here that make things very easy. I have been using Ipb before, and I am familiar with the OOP and Zend Framework. So for me anyway it should be easy to code for xenforo and create styles for it. At least I hope so. I found these guides today that were very helpful. I hope that they will be helpful to you too.
And finally, well for now.... I've been having issues with the scripting with vbulletin, it isn't very efficient. Is the load time here indicative of a more efficient scripting, or do you just have a more powerful server than I am using?