Story: Everyone knows the story, or ought to - you aren't watching this to be surprised by plot twists! If you don't know the story, read Shri Ramcharitmanas or Valmiki's Ramayana; it's worth your time. My only complaint is that they skim a little too casually over points of potential controversy in various tellings (especially leaving out material from Valmiki).
Animation: This was commissioned as a joint Indian-Japanese project with a substantial budget, so naturally the technical quality is good (for the era). It does suffer from age.
Sound: The songs are good, but "Ram Doot Hanuman" stands out in particular as excellent.
Characters: Come on, what are they going to do, make Vibhishan a robot? Everyone's pretty much portrayed as you'd expect.
Overall: This is a pretty competent production. That's not entirely a good thing, since it does feel more like a "competent production" than a heartful telling of Ramayan at times. Still, it's worth watching if you're familiar with South Asian culture, especially for "Ram Doot Hanuman" and the other songs.