I lack any actual experience to answer that question, I only know what I want: something that works a lot like the Ethernet shield, but takes perhaps 3 extra initialization parameters: SSID, passphrase, and encryption type (if it can't be determined automatically, like my computers seem to be able to do).
I did start a discussion on the topic not too long ago:
But nothing definitive came of it. In any case, thanks for liking the idea!!