The firewall in my plugin is a bit different than BBQ. To be fair, no two firewalls are the same (unless one is just copy-cat software that has been re-branded).
My firewall’s target is to stop some of the most popular exploits of WordPress sites with a focus on preventing DDoS attacks from affecting the performance of your server. You have the option of disabling any of the individual protections in the Firewall Options which can help if you need to allow certain request that might look like an attack.
I cannot speak for BBQ but if you look at the source code in their main plugin file you can that their technique is pretty straight forward. They basically deny access to your site if any of the request parameters match strings in four list corresponding to the URI, the Query_String, the User Agent, or the referrer. These are basically custom blacklists of key words or symbols that the developer has decided to block.
If the BBQ plugin works for you and it doesn’t stop you from performing the actions that you need to access on your site then you should keep it in place and add my plugin too. Typically multiple firewall plugins should not conflict with each other and if they do then one of them might be overzealous or too aggressive in their techniques.
