I've been trying to use it off and on from the very beginning of its development. And, I've been a subscribing contributor off and on for a long time, too. I say "trying to use it" not so much because Ardour is inferior to other DAWs; it isn't. It's pretty solid, pretty capable, and pretty fast, compared to all the big ones (and I've used many of them in a professional and hobbyist context). It is a great piece of software, honestly.
But, I keep ending up doing my actual work in Reaper; not because Ardour is inferior, but because audio on Linux is inferior. At least, it historically has been. It's always been a bastard step child. To run Ardour, say, five years ago required a custom kernel, a non-standard audio server that was incompatible with any of the Gnome/KDE audio servers (there were compatibility layers, but they never worked, so switching back and forth was the only way to do anything...meaning your normal desktop lost sound when Ardour was in use, I wrote a script to switch them), running VSTs was possible but challenging and limited to those that would run under WINE (often with very buggy results), the surrounding ecosystem was just a mess, in general.
If you had the ability to build a perfect system, and never touch it, it might have been OK, but I never could keep the whole stack working for more than a couple of weeks; a kernel update or something else would break it, and I'd be in for another day or two of fucking around with kernels and ALSA drivers and WINE and whatever else. It just wasn't a usable system, even though it has always been a very powerful DAW.
Many things have improved in the intervening years. Enough of the RT work has been integrated into the mainline kernel that you don't need to patch your kernel anymore (though I think there are still some folks who apply some additional low latency patches, that's probably not necessary; Linux is now, I think, competitive with macOS and Windows when it comes to audio latency). WINE has gotten better, though running VSTs with Ardour is still a rough afternoon of effort, in my most recent experience. It's been a couple of years since I last tried to use Ardour for recording; the last time I gave up (again) and went back to Reaper, so I could get some recording done without spending two days making my system work for audio.
The sad thing is that Linux has been my primary desktop for over 20 years now; I never need to reboot into Windows anymore for anything, except audio...even games are fine, for me, on Linux now that Steam offers so many great titles for Linux. I never thought I'd be saying "games are fine" before I was able to say "audio is fine", and I've been trying to use Linux for audio all those years...I was working in recording studios and attending college for audio recording when I first started using Linux, even, so it was a thing I spent a ton of time tinkering with.
So, in short: I don't know where it stands today. But, I've been disappointed pretty much every time I've tried to use Ardour for anything serious; it's not Paul's fault. Ardour is great. But, it's historically just really tough to do audio work on Linux. I'd be surprised if it's gotten as good as Windows or macOS in the past two years; it's surely gotten better. But, I'd give good odds that it's still an afternoon, or even multi-day, project rather than a "install it and press the record button" process.