I have a Chromecast (/Google TV, their branding is a mess) and Apple TV, and have used Rokus family members have. In my experience chromecast has the best app selection, it’s just running a modified version of android. It does require specific tv versions of apps, but the standards are as low as the rest of the google play store for better and worse, so anything you can get on an android phone that you’d want on a tv is probably on there. It also (with a bit of trouble) allows sideloading, and I’ve put some github projects on there like SmartTubeNext (ad-free youtube with a better UI).
It sometimes was but there were good alternatives for that. The much bigger problem imo was the lack of a dpad, using the trackpad for that was abysmal.