I don't really subscribe to Arch or Debian being better or worse than each other. I encounter issues just as frequently on both. Maybe it's a little harder to do things in Debian because the repositories don't update as often but the AUR is where a lot of important stuff is and that's a pain to deal with too.
OK, and compared to what? "Less" is a comparison, but you didn't specify what you're comparing Debian to.
Out-of-the-box RAM usage is a pretty specious metric because you're not installing Debian (or any other OS) just to have sit there in its out-of-the-box condition. Do you think a Debian server running Apache with 1000 vhosts will use less RAM than a RHEL server running nginx with 10 vhosts?
Debian uses like 200MBs of ram for a basic fresh install. That's negligible.
Unless you're deploying 500 virtual machines on a single server, that all run a single simple basic task the base ram usage of the OS shouldn't even be a factor.
I love it. More stable than many things. Preseeds for PXE.
I don't have to fuss on my fun systems.
Work systems are different. Works great when it is a nice fit. Use mostly RHEL family there, and dislike the rolling upgrades. (Breaking changes between "minor" version changes. Rarely an issue on Debian.)