As already mentioned, we've decived to use monoio, just to have something to begin with, it will take at least a few months to rewrite the core parts to make use of io_uring and thread-per-core approach (if feasible), so staying on the bleeding edge is more like a sandbox for us - we might decide to go with another runtime, like glommio, mfio or something else.
Ah cool! Just to be clear, I think you should do whatever you feel is best for your project. I don't see this in any sort of moral terms, purely engineering ones, and there are good reasons to use nightly just like there are good reasons to use stable.