Which one do you recommend for SEO purposes? Currently my board has Xenporta which is great since the members don't have to sign up for another account to make a comment. But I'm looking at other websites in our niche and they all use wordpress and have a much higher ranking. Sure, content is content but in your opinion which one is the better content system to use?
Since you already have it, I'd stick with XenPorta. Additionally, WordPress seems to be frequently having security issues, and I've heard plenty of stories of forums with an outdated WordPress getting hacked. And because we're only human, forgetting to stay up-to-date could prove virtually fatal.