It's not bad, but not great either. The idea of a man on a personal quest of vengeance against Godzilla was a cool idea, and for the most part it was executed well. The younger G-Force officers and their dull relationship with boring Miki Saegusa, on the other hand, just drag the movie down. The final battle is also far too long and, much like the other late Heisei series films, relies far too much on back and forth energy beams. Oh yeah, Little Godzilla sucks too.
In my opinion the Heisei series reached its peak with "King Ghidorah" and "Mothra". Neither are perfect movies, but they hold together well and at least seem lively and fresh. "MechaGodzilla" works on paper but as a film feels paced all wrong. The final battle goes on forever and every scene with a human in it feels like it's been edited out of existence (maybe some fans prefer that, to me it just turns it into a video game). "Destroyah" has exactly one good scene, Godzilla's demise and Junior's resurrection.