Got my GX-64 from Amazon yesterday. I think it's a very worthy upgrade, though I never had the first Chogokin one…I only had the Soul of Popynica version.
I love the weight of it. I love the dark, blueish-grey hue of the upper section of the ship. Everything is painted and looks very sharp, unlike the GX-57 which looked kind of like cheap raw plastic to me in pictures I've seen of it. I don't miss the panel lining or weathering. I think at this scale it doesn't really work and this looks like a factory-fresh version of the ship.
A lot of people have commented on how tiny the wave motion gun seems, and it is definitely smaller than before. That's partly exaggerated by the more delicate and narrow bow of the ship overall. However, if you look at the Yamato in the wave motion gun firing forced 3/4 perspective view, everything looks correct. I think the way the ship is shaped and curved now makes it feel more elegant.
This thing is FRAGILE. On the Popynica version a lot of the long, narrow spiky bits were separate pieces that you plugged in so, if you knocked into one, it would fall out. Not so here: everything comes pre-attached except for the shock cannons, the anchors and the catapults for the fighters. Be careful when opening the plastic case that the anchors come in. They are very light and tiny and one went flying across the room when I opened the container and I had to carefully hunt for it.
The lights/electronics are great. The multi-colored wave motion sequence is awesome and the bridge and engines also look nice. Once nice feature is that you can start playing one of the 5 musical tracks, and then you can overlay the wave motion sequence on top of the music. The only thing they overlooked is a light in the hanger, which would have highlighted all of the nice detail they put in there. Is the hanger "wheel" supposed to be able to turn? Mine seems stuck in one position.
That's my 2 cents.
