For me and I suspect most of my users content, presentation and ease of use is paramount. With that in mind I'd to ask the following questions.
What kind of system will be used for skinning and how much control will there be as far as modifying presentation is concerned?
Is it envisaged that there will be a CMS somewhere down the line?
Is it likely that xenForo will have the same degree of mod capabilities compared to other products?
So far I'm very impressed with what I've seen here, it might well be something I'll consider using in the future.