There's another thread where some people are piling on TOS music for being too in-your-face. But if you compare the two, I much prefer TOS music and acting style to the TNG shows.
had some of the best music ever written for a dramatic TV series, by some of the top composers working in the industry at that time: Alexander Courage, Fred Steiner, Gerald Fried, Sol Kaplan, George Duning. True, the music occasionally overpowered the acting and dialogue -- which, in the case of some third-season episodes, wasn't a bad thing.
The music in TNG and all the subsequent Trek shows is the aural equivalent of wallpaper.