Right now, it I am using a Wordpress install with various plugins to achieve what I want (bbpress for forums -- used Simple Press in the as well, All-In-One Event Calendar, a community made theme, private messaging plugin, Google Analytics plugin, Advanced Access Manager, etc). I'm finding that all these plugins still leave out functionality I wish I had or force me to consider purchasing their premium versions (which can add up to the cost of a XF license). Also it's becoming harder to maintain the current functions I have given some plugins I used to use are no longer maintained (or their latest version are buggy as hell).
For the longest time, I've always wanted a vB or IPS forum (or some other premium paid-for forum + CMS software). After some research and debate, I've narrowed down my possible choices to: XenForo and vBulletin. I'm leaning towards XF as development seems to be progressing along nicely, plugins/addons seem to be of a higher quality than most of what the vBulletin community puts out, and pricing is a lot more affordable in the short-term (long-term is still up-in-the-air). XenPorta is one of the major reasons why I'm considering XF over vBulletin.
Even after doing weeks of research, lurking around the forums, playing around with the demo, and reading through XF's site, I'm still left with some questions:
1. If I purchase a license, is it tied to the first domain I use it with? If I later get rid of the domain, can I use the license on a new domain?
2. How easy is it to create a theme for XF? Are there any resources and sample themes to help me develop my own along the way? Is the theming/styling of XF well documented?
3. I foresee needing a downloads management plugin of some sort. Does the XF Resource Manager fulfill this role? Or should I look to a community made plugin or perhaps pay for a custom-made plugin?
4. Is there any plugin (or perhaps built-in functionality) for private replies to topics within a forum (only admins, the poster, and possibly certain users/user groups can see/reply)?
5. Are there plugins for post composition level spell checking, disabling parsing of smileys in posts, multiple custom user ranks, etc?
6. I will be using the software on a shared web host. Is there a general rule-of-thumb for how large the forum gets, how many visitors daily, etc before I should consider moving my install over to a VPS/semi-dedicated hosting plan?