Great post, especially for the embedded crowd. I'm looking to start using Rust in FW development but hit a couple pain points.
* First, bit field descriptors is a huge pain - where, in C, you would define an enum for the task, there isn't a real equal in vanilla Rust, other than a litany of constant variables.
* Second, the over-reliance on nightly is a tough sell for - having inline asm gated makes it very hard.
* Third, while format is great, it's also very heavyweight. Not having (AFAIK) variadic arguments is hard, and there isn't really an equal to printf.
I would love to be proven wrong, because I have an OS to write, and would love to use Rust.