I'm quite surprised that you started off with platforms (vbulletin and invision) that are jointly less popular than phpbb. But I suppose one of the plugin developers had forums that used those platforms and I'm glad to be able to benefit from your hard work.
You have mentioned in the plugin description that conversion for phpbb is coming *soon*, and I was wondering if you might be able to provide some updates on that.
Finally, am I correct in assuming that bbconverter
i) imports topics and forum hierarchies into bbpress
ii) including the relations between topics and forums
iii) and slugs for topics and forums
iv) generates an .htaccess to place in the old forum directory so that old URLs are 301 redirected to new ones.
v) imports users including profiles, passwords, signatures and roles