After several updates that did not provide Text Zoom on every page, in the most recent version, 62.1, Text Zoom does seem to be working, at least for me. I am still seeing some weird behavior, such as screens getting larger when the slider goes down (in full zoom). I'm seeing this especially on http://worldofsolitaire.com/. But okay, there's been improvement. And thanks for decreasing the size of that hideous NS+ icon; much less an eyesore now.
Firefox 57 will apparently include a native zoom function. Will it eliminate the need for NS+? Or will NS+ perform better? We'll see in a matter of days.