Dogged by controversies throughout its lifespan, do you consider the Xbox One to have been a good console at the end of the day, and why/why not?

No. Lacked in power. Too expensive. Half bake promises that they never delivered. No exclusives that were system sellers. If you wanted Halo,Forza and Gears, a decent PC did you fine. I was able to play some stuff on a 1060 Laptop at the time. MS admitted they fucked up and lost to Sony for getting people as digital libraries grow and carry over. 

I think so. It was lacking in exclusives, but it delivered on features. It played CDs (as the only system that gen), DVDs, Blu-rays, 4K UHDs (as the only system that gen, but only on One S and X). It got backwards compatibility with Xbox 360 and og Xbox, to some extend. Play anywhere was a great feature, now it also got disc-to-digital, where it can even be used to digitise Series X games.
The price was competitive (except ar launch). It gets support to this day 13 years after release.

Short answer: no
Long answer: it sucked

If the PS4 didn't exist then sure it would be a decent option, third party games weren't THAT much worse on it and there's lots to play.

But with the PS4 existing there was very little reason to own one.

The gaming experience on it was fine, it just has crap exclusives.

Warts and all, I think it is at minimum a good console.
Pros
+Got a lot of the third-party games PS4 got
+Xbox Live/Game Pass
+Backwards compatibility
+4K Blu-ray playback (on One S and One X), CD playback
+Kinect was at least something interesting, though it should not have been forced in the purchase like it was at the start.

+Xbox One X is a powerful console.
Cons
-Base console is weaker than a PS4
-Kinect made it more expensive at first
-Did not have the true and console exclusives desired by players that Xbox, Xbox 360, and PlayStation consoles have. It's not like it had none. People like Forza, Sea of Thieves and so on. It just doesn't have the caliber people expected from Xbox or Xbox's competitors.

In my opinion? Not out of the gates. When it was Don's Xbox One, I thought it was pretty crappy. But eventually, it turned into a pretty good system.

I got quite alot of enjoyment out of mine. It had issues out of the gate due to Mattrick pushing Kinect and multimedia features over gaming features, but once the system found it's footing it was fine.

The Don era was actually pretty decent as far as exclusives. Titanfall, Dead Rising 3, Forza, Sunset Overdrive, etc. It was arguably better than PS4's first couple of years (ignoring Bloodborne the GOAT), with exclusives that you couldn't play on PC until Phil took over and changed that. Don damaged the trust in the brand, whereas Phil turned the platform redundant.

Xbox One like Series XS is a solid console, but it was overshadowed by better and more popular alternatives. If I had one with no access to other platforms, I could still have a great time playing all sorts of games. Its 3rd party support was obviously very good.

The One S was such a good looking console, my wife approved (she hates current gen consoles too big in the living room!)

Backwards compatibility and gamepass made it into the best console at the time (in my opinion) you could stack gamepass codes and have it for next to nothing :)

I failed to see any difference in graphics between my ps4 slim and One S at the time - some games still look amazing today on it (Crash Kart game for example)