since a few days i got my MED500X, and i like it very much so far.
About Wifi dongle:
i got a free dongle from my ADSL provider, i gave it a try, it is a Thomson TG123G, and it seems to work, but since it is only a 802.11b/g it works only at 54Mb/s, but it is good enough for me. (using WPA2 code)
This is the datasheet from this adapter:
http://www.thomson.net/GlobalEnglish/customer-service/SpeedTouchDocuments/xDSLGA-NA_Datasheet_thomson_tg123g_en_032009.pdf