Loose leaves left mouse button weak overall picture

As a longtime Logitech followers there was no question to accept a completely Logitech even when buying a new mouse for me.
The reason for the new purchase was a small defect in my old draft horse, a Logitech MX-518 (the direct predecessor of the G400).
There loosened after four years of service of the left mouse button, which, although not restricting the functionality that use but incredibly uncomfortable made (rattle, feeling of uncertainty hang the finger).
That reminds me the MX-518 from the mold, button layout and ergonomics but very well-liked, the choice fell directly on the building which is almost identical successor, the G400.
In principle, the purchase was not wrong, the handling was good and the usual accuracy sufficient with 3,600 dpi already far more ls.
However, after 6 weeks use (Office activities and games), I realized that the left mouse button again had some play and loose sat.
I then complaining that the items at Amazon.com and received two days later a new G400 as a substitute.
After unpacking the mouse of course I promptly removed the left mouse button in inspection and discovered to my horror that the left mouse button was loose again.
Doubtfully myself I turned to the Logitech support, but which told me that this was not normal.
As a final step, I tried then Google (which I would have to do much earlier). There I was in various reviews and forums to see that I'm not alone with this problem.

Conclusion:

With two brand new mice the same error, plus advice on some other user with the same phenomenon let me doubt seriously about the quality of the mouse. Who loved the MX-518 is prinzpiell with the G400 happy - but only if he is lucky the mouse without getting loose left mouse button.
Yet I give two stars, since there are probably quite people who hardly or not at all bothered by this defect and for this the mouse at this price is really a Best Buy.