Ghostbusters and Men in Black are similar films, structurally and thematically. Both are comedy Sci-fi films about a person or people becoming heroes to fight a threat. Despite this, there's a big difference between the films, so much that I like to describe films as 'Ghostbusters style' and 'Men in Black style'. This applies to films with a structure like this: someone becomes a new hero, or joins a new or already established team or heroes (this could be superheroes or secret agents or police or anything). The hero goes on a series of one or more adventures. Meanwhile, a threat appears (or was already in place), and the climax features the matured hero defeating the threat.
The difference between 'Ghostbusters style' and 'Men in Black style' is in the middle of the film. If the hero goes on a larger number of adventures over a longer period of time, often through the use of a montage, the film is 'Ghostbusters style'. If the hero goes on only a few short adventures in a short space of time, it's a 'Men in Black style' film. In a 'Men in Black style' film, there aren't likely to be any heroic action montages, although there may be some getting ready montages (i.e. the new indentity montage in Men in Black, or a montage in any episode of the A-Team)
Examples:
Ghostbusters style:
Spiderman
Superman
Dick Tracy
Men in Black style:
X-Men
Hellboy
Chronicles of Narnia
I can find many more films that use the 'Men in Black style' than the 'Ghostbusters style'. I prefer the 'Ghostbusters style'. There are a couple of flaws with the 'Men in Black style' First, the movie is compressed. I don't feel that I have seen the heroes explore the full range of what they might do. I'm left wanting more. This is a problem with MIB, X-Men, and Hellboy. Additionally, the heroes might act like they've gone through a bigger adventure than they actually have. This is a problem with both MIB and Narnia.
That said, I don't dislike MIB, and 'Ghostbusters Style' films can have problems too. Dick Tracy loses focus after the crime-fighting montage and ends as a confused mess.
I wouldn't apply either of these attributes to most film, probably not even more action-adventure films. It wouldn't apply it to Die Hard or Raiders of the Lost Ark, for example.