It is different, and is a great project. At the end of the day, with that strategy, you still end up with two compilers, not one single compiler, and some folks are attached to "we use this single compiler to build our entire base system." You also have to then continue the bootstrap chain to get up to current rustc, and I think folks hope that this project will track upstream more closely.

I also don't think that because it compiles to C it automatically supports all of the platforms gcc does, but I haven't personally investigated that because I don't have any of that exotic hardware.

EDIT: oh yeah and the project itself describes this stuff here https://github.com/Rust-GCC/gccrs/wiki/Frequently-Asked-Ques...