yes, i have the ralink rt2860 abgn card working just fine under linux. i had to open the lcd case and add 2 new antenna that i had lying around (one for the wifi, one for the bluetooth module i added as well). i also installed the modified bios to disable the wifi whitelist.
i got the driver source code from
here and just followed the readme to compile it. under fedora, i had to patch the driver (patch found
here) in order to get the module to compile without errors. the driver compiles fine without patches under debian lenny (which i'm currently using and loving it).
i'm using gnome and networkmanager sees it just like any other wifi card. it handles wpa (tkip and aes) just fine. haven't tried wep but i imagine it works too.
i connect at 270mbps with > 90% signal, but if it's ~80% signal i only connect at 243mbps... i think the magnesium or whatever in the lcd cover reduces my signal quite a bit.
power usage is the same as the intel cards, maybe even a little less at times.
i can also connect to 11g mimo networks at 108mbps no problem.