Ignore all negative review which says that serial number on box and product are different. Logitech product has always different S/N on box and product for some reason which I dont know.
But you have to take all negative reviews seriously about Double click because it is a pretty common issue in G102. The reason can be the cost-cutting Logitech did on G102. It is actually a very cheap mouse considering its accurate sensor which compares to many expensive sensors found on FInal mouse and Razer's mouses (PMW 3360).
But many reviews show that this mouse worked for some for a long time so it is a gamble to buy this mouse. Either way, it is upon you.
I bought this mouse because it is cheap and contains a really good sensor, I play csgo mostly. And I can later upgrade to G Pro with no problem of gripping because these two mice are exactly the same physically. If you do not play FPS games, then you can buy G402 or other mouses.