I assembled the MG Zaku 2.0.
That said, I'm planning to paint it all this time and haven't attached the exterior armor yet.
This is my sixth kit using this frame, including the Gouf series, so I'm used to it, and despite the amount of detail it appears to have, the parts aren't as complicated as the latest MG or RG, so it was surprisingly easy to assemble.
Mobility is a little more limited when the exterior armor is attached, but I think it's a masterpiece that influenced the range of motion of later kits. I think its proportions are still the definitive version among the many Zaku II kits out there.

It's a Zaku | shin's Gunpla works