I have no experience with any recent Ralink devices but I have 2 8192SU adapters and both truly are plug 'n' play. They do have one annoying but easily cured fault. If you put a machine with an 8192SU adapter attached into suspend then reawaken it, the network adapter will be missing. If you unplug the adapter, wait a second and reinsert, the adapter will work. The workaround is:
Open a terminal in an account with SUDO privileges. You're going to create a one line file using a text editor. Do something like this:
a new blank editor will open. Add one line:
sudo gedit /etc/pm/config.d/config
Save and exit.
You'll need to restart in order for the change to take effect.
There is one caution. One of my devices is a Dlink DWA-131. It's perfect. There is a thread about someone who recently purchased a DWA-131 and it was either v.2 or v.B. It did not work, even with NDIS wrapper. Dr. Chili was on the case last I knew. I also have a TrendnetTEW-649UB which is a twin of the DWA-131 v.1. I've also used rtl-8192SU as search criteria in Ebay and got some hits. The adapters I have are N150. I've seen Ebay offerings advertising N300 with supposedly rtl-8192SU chip sets. I'm not sure what the difference is and if it affects recognition and function.