This is, quite literally, my favorite film of all time. Out of everything, not just Godzilla or Tokusatsu films. Just ever.
Actually, this is also one of the few films in which I prefer the dubbed version over the original Japanese (Ted Thomas as Kubota is legendary in my mind!) - though the Japanese has one line that destroys me in fits of laughter every time:http://imgur.com/EL508.jpg
Really, you could cut all the monster scenes and I would still be massively entertained by this film as its human cast is my favorite set of characters in the entire film. Despite the faults of the film due to the limitations of the period in which it was made, I have a really hard time finding it in myself to call this a "bad" film. Given their difficulties at the time, I would say that Fukuda and Nakano succeeded in crafting an extremely lively and fun film, which also has some very stylish cinematography at times to boot.
In conclusion: Godzilla Vs. Gigan > Life