Thanks for the kind words! About the Side by side comparison, that is high on my to do list!
Regarding licensing, sorry about the confusion between my repo init and the docs. I have updated the repo to clarify the distinction: Firmware & Software: MIT License. I want people to build whatever they want on top of the stack. Hardware Schematics: CC-BY-NC-SA (Non-Commercial). Why the split? Since I am a solo bootstrapper, I need to protect the hardware from low-effort commercial clones while I get the business off the ground. But I strongly believe in "Source Available" schematics so researchers and engineers can debug, learn, and modify their own units, hence the CC-BY-NC-SA choice for the board files.
Why start fresh? It was an architecture decision. The Cyton uses a PIC32 + RFduino stack. I wanted to handle everything natively on the ESP32 for high-bandwidth WiFi streaming, which required a ground-up redesign. I also wanted to add onboard LiPo charging and the ability to experiment with different filter topologies. Building it from scratch helped me uncover a lot of subtle design constraints that aren't obvious until you dig into the layout.