I use debian but I'm not sure I'd recommend it for devs who don't want to fiddle with their desktop. Stable is great for servers and simple desktop computing, but is too stale for developers. Testing and Sid are both rolling updates, so if you don't keep updated, things can break (or more usually, change in workflow) sometimes when you do update. Ubuntu and Mint are snapshots of these rolling setups, so they stay more consistent over time.
If you don't like fiddling with your OS once you get set up, then you should be using some sort of LTS distro like Ubuntu or perhaps a BSD. Things like debian, arch, and fedora require a modicum of maintenance (not much, but it's there). If you don't mind (or like!) fiddling, then a rolling release distro is best.
Having spent years on debian, and having run stable and sid, the only really sustainable arrangement is to use stable+backports. Don't run sid! Gradually your system will become a mess and you'll end up doing a reinstall.
If you need a library that isn't in backports, just compile from source and install to /usr/local, it's not hard!
Datapoint to support you: this conversation reminded me to do an update on this debian sid laptop, which is a couple of months un-updated. about a gig of downloaded updates... and I came back to my lockscreen which had a whole new look, and my desktop wallpaper had changed (I think I was just using the default before, so understandable).
It's fine because I understand what Sid is about and this is to be expected, but I wouldn't suggest this to a naive user. And since Testing gets these changes in short order, I'd stay away from that as well if the user isn't comfortable fiddling.
So yes, stable + backports, unless you're comfortable with change/fiddling (same with any rolling distro).
If you don't like fiddling with your OS once you get set up, then you should be using some sort of LTS distro like Ubuntu or perhaps a BSD. Things like debian, arch, and fedora require a modicum of maintenance (not much, but it's there). If you don't mind (or like!) fiddling, then a rolling release distro is best.