I've had excellent experiences with a few different Roku TVs. I think my old dedicated Roku was a tiny bit faster in some menus but in the end it's been the same experience. I do acknowledge the privacy implications of Roku and the fact they inject some ads on the home screen but it's probably been the smoothest streaming platform thing I've used.

I had a recent model Vizio. That was absolutely terrible. Eventually the power supply killed itself and I haven't bothered replacing it. Over a decade ago I was a fan of Vizio, that one purchase forever soured me on the brand. I'll never buy and never recommend them again.