Apple

A few reasons:

It provides a quality out of the box experience.

Lack of bloat (back when I bought my phone through my carrier, Apple was the only one to say fuck you we’re not installing your garbage carrier apps, which I appreciated).

It’s popular, so most things out there in the “real world” (here in the US) are designed to accommodate it. This includes accessories.

Good hardware resulting in reliable, consistent performance.

I prefer Mac to Windows, so the integration is convenient (though it’s not really something I’d seek out).

Apple stores are available for support. Shipping off my phone for repair or something doesn’t appeal to me.

Apple Watch is nice.

Google’s Pixel line accomplishes a lot of this too, aside from the things that depend on popularity, so I like Pixels too.