Yes, it's true the film has a lot of grain, but nowhere near as much as, say, "Friday the 13th Part III" the world heavyweight champion for unloveable grain. And surprisingly there are plenty of dark and indoor scenes with very minimal grain. The other picture quality caveat is that a lot of mid-long shots are sometimes lacking in sharpness; and this does not always look like a stylistic choice. But there are countless close-ups and plenty of long shots which are very sharp. Especially the close-ups often have unbelievable depth and plasticity for a 25 year old film. When Winston is shown in close-up during the showdown with Zuul, this looks like a film from this or last year!
"Ghostbusters" has also been accused of having washed-out colours on BD, well the fire-engine red of the ecto-containment system in their cellar is superb and colours generally are very good; nothing like "Halloween" which is a little washed-out. Dana's appartment looks a bit faded, but I think that's how her furniture is supposed to look. Some of the FX are outed as a bit poor by HD such as the "streams" and the dogs, but the library ghost, Slimer, and Mr Stay Puft all look great in HD. And there is a shot of sky-scrapers a little before Dana's roof blows that holds its own with the typical HD showcase shots of many films made after the launch of Blu-Ray as a format. The soundtrack is occasionally a bit weak but for the most part more than acceptable, above all in the final showdown scenes and whenever the theme music is pumped out.
The film is a classic and needs no recommendation at this stage. If you are considering upgrading, do it unless you have an absolute allergy to grain. The Sony trailer for it as seen on "The International" is very fair; showing typical better and worse scenes, but the majority of scenes are in the former category. If only "Gladiator" had been released like this. Those who will sacrifice detail to be grain-free could have turned on their BD player's processing (as some might prefer to do here) and everyone could have been happy. This is a BD release full of sharpness, depth and detail, and, yes, occasionally more grain than some may like. At this stage most people will have established their expectations and tastes for Blu-Ray. I hope this review makes it clearer whether this disc is for you or not. Highly recommended.