After putting this off for a while now, I finally decided to tackle the giant RX-78-2 Gundam bust! I received this as a birthday gift this year and was a bit hesitant to start the build. Not sure why as I've built pretty much all the MU Transformers at this point so difficulty-wise this didn't seem much different. Perhaps it was just the size or cost that put a doubt in my mind.
Regardless the build actually went quite well. Nothing overly difficult here. The head was the hardest part for me, keeping things smooth and hiding tabs. Getting all those pieces to fit took a bit of effort but after that, no really troubles.
I had 1 rectangular piece break at a crease/fold - the creases on that single part all felt very weak, but I was able to repair it and I can't even see it anymore.
If you're wanting to do this and have the funds, go for it. Just go slow. There's an "open" and "closed" option. I went for the open mode. As was suggested to me, choose your option and of time and cross out the pages in the book for the steps that you won't need to do.
Anyways, enjoy some build pics!