tsellers
100 W
I'm no expert, but that frame looks to me like a copy of a basic split pivot design (for example, Trek bikes*). It appears to me that there is a concentric pivot around the rear axle which connects the chainstay and seatstay. Split pivot are said to do well for bump compliance like the single pivot, but split pivot is better at downhill braking. Most reports indicate that the compromise was in the pedaling efficiency. I'd imagine you prioritize what you want from your bike, and then choose a frame with the pivot design that matches what is important to you.
* Back in 2012 Trek had to deal with a lawsuit that claimed they stole the Weagle design. Both are very similar designs. Trek's patent prevailed. But for other manufacturer's that wanted to use this design, the cost of licensing the patent would make for an expensive bike. So, if this Chinese frame is a reasonable copy of either of those patents, it's another example of how in the modern world, your patent may not be of much benefit to you in the long run, because as you pointed out, this Chinese frame appears to be inexpensive yet may use what was originally a design made expensive due to the patent.
