Cool, I've never seem the old Godzilla movies (I've only seem some new ones when kid) nor Gamera, but I know that they are enemies.
Yeah they're rivals in popularity anyway, from different companies. I've never been a big Gamera fan myself, maybe if I watched more of the films but I doubt it. Godzilla though, I've been a fan for a loooong time. I had
Son of Godzilla on VHS and watched it a lot when I was all of 4 or 5. Had about 5 or 6 of the others on tape at various times in my childhood, and have made a bit of an effort in more recent years to see the ones I missed.
I must admit though, the Kaiju genre (particularly films from the 60s and 70s) is often a lot more boring than many people who've never watched the movies probably imagine. Suite-work was difficult and expensive, so in a 2 hour monster movie you might get 15 - 30 minutes of monster battle/rampage. The remainder being taken up by characters you don't care about doing things you're probably not really interested in.
There are exceptions of course. The original
Gojira and
Godzilla: King of the Monsters were good character dramas for 1950s monster movies. And I would always recommend 1991's
Godzilla Vs. King Ghidorah as one of the best in the series (possible Anti-American sentiments aside) where the human plot ties in with Godzilla really well. I'm a bit of a King Ghidorah fanboy but it really is a fun, engaging movie. But when the aforementioned dullness of uninteresting characters taking up too much time gets bad in this genre, it can get
really bad.