Welcome to PEEL, core!
The quality of Futurama episodes on Netflix are the standard quality that you'd normally see when you watch it on TV.
But you need to look at your internet connection. If you don't have a fast internet, then your quality is going to be pretty bad.
Of course, The type of TV you have plays a major role, too. If you have a 4:3 Television (Older model tvs that usually like square sized), Seasons 1-4 will fill the screen, and look gorgeous. While newer episodes will be in a widened format, not filling the entire screen. If you have a 16:9 television (like LCDs Plasmas, the HD tvs that look wider), than seasons 1-4 will be displayed in 4:3, square sized, and keeping a good quality in check. Newer seasons would be full screened, and will have jaw-dropping quality.
I know this, because I watch Futurama on Netflix myself. (I'm too lazy to get a disc from my bender-head collection and put it into my PS3.)
thanks so seasons 5+ is 16:9, also the bender head collection looks sweet!