The HL KV-1 uses plastic made from recycled rat feces. Not sure what they were thinking there. Seriously, it's as strong as softserve frozen yogurt.

The other 4 HL's I've played with have been nice, stiff plastic that doesn't seem to easily break. Well, except for the TC hatch hinges.

Without ever laying eyes or hands on a Tamiya, I can guess the plastic is going to be much higher quality. If it isn't, Tamiya needs to be drug out back and shot for charging what they do.