I'm rating as a developer who has been working on the code in this plugin. It is one of the best coded plugins I've found on WordPress. A wider use of PHP functions and more innovative procedures than many premium plugins that exist.
I can see a secure and safe plugin. That matters a lot in a plugin of this nature but despite this it is often less considered by many WordPress users. Even if there are bugs in this plugin, it is still one of or possibly the best place to start with WP phpBB integration.
I'll be adapting some functions for our own WP e-Customers plugin which has a modular/section approach. I looked at all bridge plugins through research as WP e-Customers is to have WP to phpBB (not phpBB to WP) functionality. So we're not making a rival but a different tool catering to a different approach. I've already mentioned WP United in my source comments.