As for the Universal WiFi adapter, the way it works is, it grabs an IP and runs in bridged mode. So it has all the communication up and running with your wireless network and the device (controller in this example) doesn't even know it's on wireless but thinks it's on wired network.
Now wireless by nature is slower. Reason being is it runs in half duplex mode. Half duplex is where only one device at a time can talk, and it can only talk not recieve at the same time. This is why a wired full duplex mode is always preferred so you can have two way communication.
Back to the adapter, I like them a lot. I was streaming full ISO Blu-Ray movies with no buffering or latency. So these adapters can do full Wireless-N speeds. I highly recommend them, and have had zero issues. I have one on my controller today. Cheaper than the Arduino Wireless shield they sell. Much more versatile as well.