I don't get too excited by test screenings. That said most everything I've heard is positive. If the descriptions I've read are accurate, I'll be satisfied with the story. Didn't want to get spoilery but it really doesn't matter because in the context of visually seeing the movie it will all be new.
Besides we KNOW Godzilla has to survive, otherwise Kong will be twirling his weiner in the next movie.
Also it will be a bit different in certain contexts of what we know as Godzilla....and some the same. The key is newbies will not have that history to look on and say they saw that before or, I thought they were friends, etc. The indelible things we know are "Godzilla generally gets beat up before winning a fight, Mechagodzilla nearly killed him before he used lightning to power up, Rodan sacrificing himself to beat MG2 etc. Mothra always "dies" etc.
We fans will see it, and from all accounts, we will get lots of pretty things to look at and lots of monster fights.
One review said the only "drawback" they saw was it was shot out of a cannon and never relents. I will take that any day to "When are we going to see something"
That is the recipe, if it's good, to have legs because it creates "Whoah, I missed something, and need to see it again" effect. Last movie was easy to follow because there was so much downtime between fights and they were so short.
Also I've heard two end credits scenarios....one is as posted above and the other while similar had a different creature depicted....
Either way I'm going to call it, the creature depicted in the post credits above is accurate, after brawling a bit with each other (And maybe taking out some of the other Titans along the way, the two Kings have to work together to defeat the ultimate opponent created by the eco-terrorists. One that could be exceptionally awesome in CGI form. Sure it's the same concept as Batman V Superman, but can be done right....
It's like wrestling...you can have the two top babyfaces square off, problem is who goes over? It's like Sting V Undertaker...someone will win but then one has to lose and tarnish his legacy, what positive does that serve? You bring in the monster heel and they team up together despite their differences. In the end you are left with mutual respect and both carry on defending the planet.
You must show no mercy, nor have any belief whatsoever in how others judge you... for your greatness will silence them all!