although spack had a lot of problems with tensorflow for years... But yes, in general it works best nowadays and with clingo coming up, I guess it will eventually beat NixOS (because hopefully browser-like dependency trees become fast then).

(and I still don't get the advantages of an advanced build system like bazel, where I first have to build the right version of the build system (including all patches which might crop up with new libcs in vendored dependencies), and then it takes ages to compile (compared to any other similar software...) and I still have to fix the libc bugs...)