I think that's a trick question, Debian's outdated but stable binary software is in many way completely antithetical to Gentoo's philosophy, but on the other hand, it's still Linux, and absolutely a viable alternative regardless. I'd love to hear some more opinions about the state of the portage tree though, as a new and naive, but dedicated, Gentoo user, I don't have a sense of it's history or the state of the projects resources.
The thing I'm imagining is that if there was something I wanted the USE flags for, I'd just end up compiling myself in a prefix. I already do this for some packages because of the issue with Gentoo removing things they consider stale which is the problem.
I don't need USE flags all the time or compiling everything with -O3 -march or whatever, for most things it's just a plus that it might be faster. I think the one thing that might actually matter for me is in Gentoo fixing broken things is more direct, just compile, while I've had issues that persist on ubuntu even after reinstalling something. It just felt like there was somehow "stale state" in my OS which even sounds ridiculous saying. But, at this point, I can't handle breaks in portage because while you can fix things, it requires mental effort on my part and I'm tired of it.
EDIT: reading your comment, if you're asking for my opinion I mean look at this in particular:
ioquake3 was literally removed from portage for this "bug" which even if you accept that it's a hypothetical issue has easy patches that were never included, and it was removed, essentially removing hosts of open source fpses from portage! I even read a forum post talking about "upstream" not caring...upstream? ioquake3's release was charity, it's not like an active project.
This has been happening for a while. I've been here since 2008 or so and the instability and removal of slots within months has gotten out of hand. Again, the tooling is great, emerge, eix, the whole system of configuration files is awesome and I'm just used to openrc. I wish I could keep them but the slot removals in portage has just become such a chore to deal with.
Gentoo packages, by virtue of use flags, do seem like they'd take more effort to build and maintain, but I don't know enough about gentoo packaging as I'd like to :p
I have packaged for both Debian and Gentoo; packaging for Gentoo is way easier and more fun, one reason being that (simplified) you're dealing with a single Bash file rather than a magic Makefile and things split into 20+ small files. The difference is huge.
