Disclaimer: Have been an apt shadow for a couple years and ran some PPAs on both launchpad and private servers.
Personally, I think the approach that upstream Debian uses in order to not include the headers of libraries with the binary builds is wrong.
Nobody has time to deal with over 30 GIGAbytes of hard drive memory that is just there because I wanted to rebuild a damn library of 20kB. That is a total fail, architecture- and build-system wise.
As long as Debian separates between distributed binaries, and -dev packages which include all source codes and headers - I would not recommend it for software development.
This is the exact reason of PPA fatigue, where end users have sometimes dozens of versions of the same library installed that is also an absolute security nightmare to begin with.
Reproducible builds are worth nothing if everybody has to use a PPA of some random untrusted blog post on the internet (omgubuntu anyone?) because Debian's packages are too outdated. Usually those PPAs are heavily outdated as they are built once and then abandoned for years.
Libraries are not upgradeable due to how other packages depend on them. They cannot be rebuilt without having to rebuild the whole operating system (have to rebuild X again? Well, gonna stop here then.)
Sorry for the rant, but I think in order for DUR to work in practice, these conceptual flaws have to be fixed upstream first.