The quality of internet TV depends upon the maximum resolution they use, speed of your internet connection, and how busy their servers are. For example Hulu is usually 480p at best, except for some movie previews that may be 720p. But one Sunday afternoon when there servers must have been busy, my connection dropped to something like 233p.
Netflix HD is 720p with stereo sound (maybe lower resolution on a PC than on a dedicated device). Likewise one Sunday afternoon when their servers must have been busy, one episode of an SD TV series dropped to lower than SD quality. But the 720p HD movies do look good.
BluRay is 1080p with all sorts of digital sound if you have a surround sound system. Some are 60 Hz if recorded in HD (Europe might be 50 Hz) and some are 24 Hz to match the cadence of film sources.