Not having been 100% happy with the Simple:Press forums to begin with, their decision to start charging for access to their support forums without warning was the last straw for me. I decided to go back to using reliable phpBB. There was just one glaringly big problem with that. There was no converter to go from Simple:Press to phpBB.
Despite searching all over, I couldn’t find one. The best I could find were some clunky workarounds or half solutions. These usually involved attempting o convert Simple:Press over to something else first and even the converters for that usually weren’t fully developed. Or they involved converting just the members from a WordPress site over to phpBB. I really wasn’t happy with any of the options that I came across.