Vector displays are one of my favorite things! If you ever get a chance to play with one, I highly recommend it. Playing with a friend's Tektronix terminal was stunning for me. The Vectrex was an amazing little console, and it's a shame it didn't take off. There's an alternative world in which computing never got overtaken with the urge to put photorealistic pictures on every surface, and that world is so much neater…
I was obsessed with vector displays as a kid. The standup versions of Star Wars and tempest looked so futuristic in comparison to the other stuff out at the time. Vectrex also looked a whole lot cooler than the Atari 2600 but I guess people like color and those overlays did not quite cut it :p.
The tiny all-in-one monitor didn't do it any favors. People wanted to play on their TV, but that obviously wasn't going to work with a vector-based system.