Earlier quoted context omitted.
I've found QEMUs microvm to be faster at boot while having nicer tooling and a cleaner upgrade path if needing more features. Aside from hype I'm actually not sure why anyone would still use firecracker.
Mainly because of the much larger attack surface of QEMU.
I can't quantify how much of that surface is also reduced with the microvm machine vs other parts of QEMU vs Firecracker... But fair enough point.