Roku hardware and UI is superior to anything on the market. YouTubeTV is decent, but the competition is robust.
Granted, there are some objective measurements between different devices, such as Dolby support and format support, but that's typically for the most advanced consumers of content - not the vast majority of people who just want to watch certain content.
The clicky, rubbery buttons and the responsive UI is amazing. After 5 minutes of use, I was hooked and bought them for all my TVs. This is the single biggest differentiator with Roku and other hardware.
I have to agree. I've used Apple TV, and while its UI is fancier, it lags, crashes and just doesn't have the same "ergonomics". Something as simple as toggling captions and changing picture modes while paying a video is so much easier on Roku. And, all the menus provide by the Roku OS just feel snappier.
The Chromecast UI, ie your phone, has a far better interface. I'm never required to hunt and peck a password or search term.
On top of that neither my PS4 nor Chromecast injects ads.
I have never used a worse piece of smart TV software than a Roku so I'd be keen to know what you're comparing it to when you call it industry leading.