From my experience, its much more stable. Sid is "unstable" by Debian's definition, but Debian's definition of Stable is a lot more intense than most other distros.
If you want a little more stability but still rolling release, do Debian Testing. Packages are only really delayed by 2-10 days (except during release windows where they do branching). The only criteria for something getting into Testing is that it passes all tests while in Sid for multiple or all supported platforms.
But overall, Sid is fairly rock solid. If anything I think Rhino Linux should have taken Debian Sid or Testing as a source, adding all the niceties/desktop/sane defaults of Ubuntu that they like. and released that.
I've been running sid aka unstable for years now with very little to no breakage (well, the recent transition to pipewire was a bit fun but seems to have settled now and was never critically broken)
I tried using testing first but did experience more breakage there for some reason. I wonder if that was just bad timing, but like I said, "unstable" has been rock solid for me so I've never looked back.
The next version of Vanilla OS[1] will offer immutable point releases based off of Debian Sid with some extra tools like an integrated distrobox and "sane defaults" without foregoing choices, moving away from Ubuntu after the latter announced ending support for Flatpaks in favor of pushing snaps.
Sid is not, contrary to what others replied to you, a proper rolling distro. Particularly during the times when there are freezes for a new stable release, the repositories can become broken in a way that you may not be able to install software you want because its dependency chain is not fulfilled correctly. People who almost never install new software might not notice the issue, as it's not like sid will break what you already have installed -- as long as you don't say yes to a full-upgrade that shows a concerning amount of removals.
I've had experience with it and Arch in my rolling days (I am now a debian stable user, and use flatpaks and pet containers when I need newer software and feel much more at peace with my systems now), and Arch would, in my experience, never be the source of breakage. Things do break at times on a rolling release distro, but in the case of Arch, that would be because something upstream changed in their software, not because of the packaging of the distro itself.
Debian testing is not the answer either. When there are bugs that make it to testing, they can linger for an incredibly long time. At least, on sid, or Arch, it's more likely to happen, but also will get fixed quickly.
IMHO, the current landscape has solved the whole reason that made rolling desirable. With flatpaks and pet containers, there's nothing you could possibly miss, while you run a stable, unchanging system underneath. If you need support for hardware so bleeding edge that there isn't a backported kernel yet, I'd still find it less effort to package my own ( https://www.debian.org/doc/manuals/debian-kernel-handbook/ch... describes how to do this succintly. It's not as much work as it sounds ) from upstream until backport repositories support my hardware, than have a fully rolling distro on my computer.
I've used sid on my machines for decades, as have many other people. Works great. It's not an official "release" in that it's not all tested together, but neither is Arch, really.
i'd imagine sid is far more stable than arch, but that is just my anecdotal experience.
plus ... ubuntu is debian. can't rly imagine why you'd want to base a new distro that is debian-based on something other than debian.
arch is a cool distro that I definitely respect, but I don't think it is appropriate to use for a workstation that you need unless you are on a filesystem that will do snapshots before package updates such that you can easily rollback. ie btrfs/zypper.
Sid has always been pretty good for me. I run a mix of Sid and Stable machines. It really depends on what you're looking to use the device for, but I've never found severe breakages or anything on Sid. I probably wouldn't run Sid on a server though.