Zhengdefu/Kitech/AA (I think it's one company) are well known for copying academy and italeri kits. The overal quality is much lower then with the
real kits.
There also was a chinese company that copied hasegawa kits, I forgot there name.
I made the mistake of buying some Zhengdefu kits. The price was very low (€2,50) so I bought 3. The qualty of the plastic, decal and clear parts is so bad that I am not sure wheter I am going to build them.