I have used my first-model/first-generation Roku Netflix Player (later renamed Digital Video Player) for Netflix. It is showing its age:
- maximum resolution on the Netflix channel is 720p,
- it lacks subtitles and alternate audio tracks for the Netflix channel
- and when the Netflix/Comcast agreement was inked the stream this original-generation Roku uses wasn't improved, unlike modern Rokus and many more recent devices, such as my TV.
Since I haven't gotten around to replacing the ancient Roku with a Roku 3, what streaming I do from Netflix I have been using the Netflix applet on my TV to do the streaming, and it has been doing it pretty well, getting 1080p streams. However, it seems that software updates tend to be limited to just a few years, so as soon as my TV has issues with Netflix due to lack of software updates, I am planning on replacing my ancient Roku rather than replacing the TV ... unless the TV needs replacing for other reasons.
My LG Blu-ray player is too old to have software that properly handles Netflix now (particularly for shows with more than 99 episodes, such as Mission: Impossible).
I never connected the newer Sony Blu-ray player to my Netflix account. Some day I just may do that, but right now the TV seems to do an adequate job. I suppose it is worth testing for comparison purposes.
My thinking on the Roku is that the primary purpose of the Roku is to stream content, originally to stream Netflix content, so Roku has a vested interest to make sure their current products work with Netflix; whereas when it comes to "smart TVs" and Blu-ray players, the Netflix application is a check mark on a feature list, not a primary selling point, so it might not always be the best way to stream Netflix, though the Blu-ray player is probably the best way to enjoy Blu-ray discs I rent from Netflix.
One thing I have never used my HDTVs for is TV! Specifically, I don't use the tuners in the TVs. Instead, they are fed via HDMI (Blu-ray players, Roku, HD DVR) or composite & component (the DVD player/VCR).