The vast majority of things labeled “Roku TV” are sold by TV companies like TCL, Hisense, Westinghouse etc. “Roku TV” in that sense is just a new buzzword like “Color TV”, or “High Definition TV”. Most of the companies selling Roku TVs, in my opinion are second/third/fourth tier TV companies, but your opinion may vary.
Roku did just recently come out with their own line of Roku-brand Roku TVs. Maybe they’ll turn out to be OK, but they haven’t been around nearly long enough for me to trust them. After I see some 10-year reports, that may change.
Until then, I’m happy with my $30 Roku Express hooked to my 16-year-old Samsung TV.