Google TVs have very customizable closed captioning with regard to backgrounds,caption colors,fonts,and writing styles. I can even have cursive writing! (Ugh!)
Same thing with Dish Network. The captioning for Dish subscribers emanates from the satellite box however,not from the tv.
CapTel phones also have extensive customizing re: closed captioning.
Personally,I like black background with yellow lettering,white background with blue lettering,and black background with cyan (a light green) lettering.
Presently,my Google TV (connected to Dish Network) and CapTel have black
background with cyan lettering. Very readable to me!
Hope you find a captioning format on your devices that you like.