I think they made the Windows key get disabled in Game Mode as a way to get around misclicks, but I've never had that problem. I've found Profile 1 with Num Lock, the poll rate set to 1000Hz, and latency to 1ms to be by far the best setting.
Also, my silence is because I'm waiting for someone to give a clear way to assign F13 - F18 to the macro keys so I didn't waste $30 on a keyboard I didn't actually need.