I think I'd have to give it a B+ myself.
Yes the battles and effects were truly
spectacular, the score was fantastic (can't wait to download it), and I loved the world-building and all the little design details that went into the movie.... but there were still some things that kept me from fully loving it.
I just didn't find the characters all that compelling, and the dialogue was a little too
corny and simplistic for my taste. Yeah I get that it's the anime style, and they did a great job emulating
it, but it still just didn't really grab me. And after awhile the sameness of the battles and the Kaiju started to sap my enthusiasm as well. Every fight seemed to take place in the rain or in the water, and the Kaiju all just looked like slight variations of the same design. I was really hoping we'd get a LOT more variety than that.
Oh, and this probably isn't a good sign, but my XD theater was less than half-full. Which I usually don't see with movies showing on that screen on opening day...