I thought the anime Godzilla Trilogy was an interesting experiment with some neat ideas, but my enjoyment of it was a bit hampered by long stretches of boredom that I took for padding. I don't feel like it needed to be three feature-length movies. Maybe three hour-long episodes would have done the trick? Still, I think it's worth watching especially if you're a fan and want to see a lot of ideas from the series implemented in unconventional ways.
Oh, and we're beginning to be absolutely bombarded with King of the Monsters TV spots showing massive amounts of new footage. If you're like me and want to remain relatively unspoiled you're going to have to actively avoid stuff!