Hello :)
I've started using RPG in a Box several months ago for a first-person adventure game called Nékromegà, which Justin has featured on his website. Here's my dev blog if you're curious: nekromega.lectronice.com. I've been providing various feedback and bug reports along the way, and I'm very happy to see RPG in a Box grow, especially since it has recently been greenlit on Steam.
I'm currently on vacation so I probably won't be very active before a couple of weeks, but I have a big outdated list of notes and suggestions. I'll try to tidy it up a bit and share what's still relevant here.
By the way, I'm posting this from the Itch app, and it's pretty handy to both get updates and give feedback. Cheers!