I agree, Windows Phone was pretty good as an OS. The live tiles, the hubs, the pinnable tabs etc made it pretty much a far more efficient interface than Android or iOS, which were rudimentary "grid of icons". Barely different from the dumbphones of the 90s. The Windows UI was different to be sure, so there's a learning curve, but I feel it was far more elegant, and simpler to use. Obviously, iOS and Android copied the general cleaner, minimalist style later.
Too bad it was too late and hence didn't get any support from app developers. I had a Lumia a long time ago, I do recall it had the best camera on the market at the time. It was going well for a few months, but then I hit upon an app which was only on Android and iOS. I had to return it right then.
That said, Windows 10 now encompasses all form factors, so I can see a future once foldable displays and such hit the markets.
I don't find much of a difference between Android or iOS, personally, though I do prefer the freedom of Android - which is why I use it. iOS feels like a dictatorship, albeit a comfortable one.
All kidding aside, yes, the cameras were top of the line on the flagship models.
As I started with Windows Phone, I didn't have an actual learning curve, as it became the native approach for smartphones for me.
The camera and camera software (along with maps) were good a long time, but now they are ruined too, at least on those parts I want.