I ordered this keyboard based on personal recommendation of a friend, who swears by everything Logitech.
Sadly, I've just called Amazon, and received return labels, as the keyboard stopped proper operation earlier this week, the "A" would start repeating without any reason, and only turning the keyboard off and back on would stop this, only to see it start again after a few minutes.
As for the time when it was working? I don't really have any complaints (never had a problem with my W7-64 system, or the supposed latency), although the mouse is pretty battery-hungry (two battery changes in two months), which seems way too high for someone who mostly uses the keyboard.
As for the return process, the Amazon website isn't very helpful with regards to defective items that need to be returned after the 30-day refund period, and in the end I had to resort to calling them.