This seems pretty unanimous so far. Terror of MechaGodzilla is simply the superior film. There really shouldn't even be much of a debate here. If you break down Godzilla vs. Mothra, it simply takes story elements from the original Mothra and Mothra vs. Godzilla, with it's only original contribution being Battra. I will say that it has the superior score however, but only because I've always held the various Mothra themes in high regard.
The human element is simply better, where the various characters actually contribute to the conflict and advance the plot in interesting ways, and even play a role in the finale. The characters in Godzilla vs. Mothra just disappear after Mothra rises from her caccoon. Even the characters in the original Mothra vs. Godzilla had something to do. Many have pointed out rather accurately that it was a rather BS subplot, but it was at least something.
The monster action of Terror far outclasses Godzilla vs. Mothra. The Heisei series, at that point, was getting into it's "beam battle" faze, where the suits became bulkier and bulkier where the only real action they could showcase is just a big laser fight. Otherwise, it's just the overweight suits and muppets bumping awkwardly against each other with sparks flying everywhere. MechaGodzilla's Counter-Attack's action is so vibrant and fast paced, with all of the suits capable of full ranged, and swift motion. The close-ups of Titanosaurus and Godzilla boxing are a first and only for the series.
The way Terror is filmed, you could tell they were pulling out all of the stops. Last film by Ishiro Honda, and supposedly the last Godzilla film (at the time), and it shows. He always had a way of filming that made these monsters seem truly titanic, mostly shooting from a lower angle looking up. But his films have a true feel of their own that seems to have been lost. The only one "recent" or modern film I can say captured that similar style/feel is probably Godzilla vs. Biollante... and that was 26 years ago.
I like Godzilla vs. Mothra, but it doesn't hold a candle to Terror of MechaGodzilla.
