Even in China, most cubers have no idea about where Type A/C come from. Only those cube sellers know where the producers is and they keep it as a secret for the reason of ... Aha, you know it, don't you
Type A/C is the mainstream cube in China.
Type A have got a very good quality. However, due to its heavy weight and bad cutting-conner, it is considered to be a beginner's cube. I personally use Type A in practice, but I won't use it in competition.
Type A mode 3 is very good at cutting-conner. But its plastic is not very good and the centre piece is a little bigger, thus makes it don't turn very well.
Type A-II is the first Chinese DIY with a logo

It is a preliminary product just like Type A mode 1/2. I personally appreciate the design. However, as I say, it's a preliminary product, and it has so many flaws to be fixed.
Type C is in fact not a imitation but a duplica of the Rubik's DIY. They use the same model (in fact, Type C use one of the Rubik's models, you know, Rubik have several models), only differ in springs/screws. However, Type C has made some improvement according to Rubik. And it develop more colors also. At first, Rubik's DIY only have a black color, and black plastic is always worse than white one. So, IMO,Type C is better than Rubik's DIY to some extent.
Type D is much cheaper than A/C in China, in fact, less than half the price of A/C, because it's not made of ABS but some kind of bad-quality plastic. However, due to its high cost performance, it is a suitable cube for beginners.
Type E(Diansheng) is never considered to be a speed cube.
Type F(ShengEn) is the new product of the producer. Type B sucks, Type F succeeds.