This leaves you with the Ralink drivers which are source downloadable from Ralink's website, but they're kind of buggy. If you fiddle with them it's possible to get improvement, but getting them to compile and install on 12.04.1 Ubuntu seemed leave them in a state where they drop connections...
It's not like the hardware is horrible..
On Linux if you get the B2 revision of this device it will use an RT5572 chipset; which is not supported (to my knoweldge) by Kernel drivers listed on wireless.kernel.org as of 11/2012