I have been using Toit as firmware for many years by now. I was one of the early adopters and is still using Toit this day in production devices globally. It is super fast on EPS32 MCU's and reliable.

The price is zero, meaning it's free of charge to use as it's an open source platform.

All support is handled in Discord and online there is a comprehensive documentation and package library available.

UI is of cause text based as it's a language and not an application as such. Review collected by and hosted on G2.com.

The downside for new users is probably that you need to read and learn the syntax and the overall idea and vision in Toit. Review collected by and hosted on G2.com.