I've upgraded the wifi card in my Asus G53JW to the 6205 in order to get 300Mbps.
However, I'm having issues with the card having major lag spikes while gaming. I don't play too many games online on the PC, but I'm noticing lag spikes lasting a few seconds and happening every 2-3 minutes or so.
The intel website suggests to turn of the power management feature so that the card is always on, but this doesn't help at all.
Other wireless devices are fine and hard wired is fine. It's just this laptop that has the issue.
I used to have lag spikes etc on Intel 5100 when going on youtube videos using WiFi. Someone told me of this program called WLAN Optimizer. I suggest you download it and follow the guide online. It should solve your lag spikes.