Well clearly Beijing sees the deal as desirable and I can see a variety of reasons that build the final decision.
For those who still doubt the genuine nature of the agreement, please note all that any officials on either side are denying is that the deal is signed, not that a deal exists and is on the table.
I am somewhat disappointed by the disparaging attitude of some posters to Russian Military Technology. China may well be pulling ahead in many critical areas, but they are still behind in others and if these are areas; system, subsystem, production techniques etc, which China can catch up from this purchase, then I say fine, why bother trying to reinvent wheels that others have found perfectly good and working solutions too and save all the time and money.
I also suspect time is a new critical factor in all this as the security situation in the Pacific East is undoubtedly deteriorating, with the re-pivot upsetting the strategic balance. In that sense a show of greater solidarity between the two Asian powers sends a powerful signal to the region as to be under no illusions or make serious strategic miscalculations.
No, it is not a fact, but your assumption, that 2 sides are negotiating at the moment, as there is not single hard solid proof of it.
Even though it is an educated assumption, and to a certain degree that I also reckon, it is still an assumption, not a fact.
As for your "no need to reinvent wheels"argument, it is mute in case of China who wants to be self-sufficient on all key techs. Yes it means that sometimes, perhaps in most cases, reventing the wheels at higher cost and longer time - purely for the sake of completely understand the basic key features which can not be obtained via purchasing an end product offshelf.
I am not claiming that China is ahead in every field and has nothing to learn from Russia, but this Su-35 purchase, if it's true, as many commenters such as "engineer", "lion", etc already argued against, doesn't have ANY standalone solid reason thus far, being either engine, radar, alliance reason, capacity reason, or benchmarking, or gap-filling, or (Russia) industry- life saving, or someone's kickback fees, or whatever.
To sum up, buying Su-35 for its own merits is irrational.
Under 2 scenarios, though, the deal could be true IMO:
A. it's an order from THE big boss, without any explaination. Completely irrational it is, it is merely an order, no reasons have been given and no questions should be asked. Full stop! Or
B. it is a part of a bundle-deal in a sense buying Su-35 being a pre-condition (demanded by the Ruskies) of a much larger deal/s for later on, either about millitary, or about civilian, or political, or all of them. That's perhaps why the 2 sides might be still talking and none is willing to confirm it 100%.
