I trialled another (free) forum software (phpbb) for a year alongside Invision Community software in 2011, and looked at many others. I decided to go with the self-hosted, paid version of Invision Community. We now have over 2,000 members, but that's not the impressive aspect. Invision Community allowed us to build one of the largest (and perhaps the largest) repository of free information on stretching, flexibility, and mobility available anywhere on the net, and we built a thriving community organically in the process. Sincere thanks.
Kit Laughlin
https://kitlaughlin.com/forums