I bought the Logitech g613 back in December, have yet to change the batteries and have had zero issues with it. Having the ability to switch between the USB dongle and bluetooth has also allowed me to use it a bit like a KVM for switching between two machines too. I bought this after coming from a Logitech G11 and the keys have a much nicer feel to them than the plastic domes the old KB had.
Only downsides to this KB is it uses two double a batteries to power, there is no backlight and I miss my scroll wheel for volume up and down.