A big sell to me is: Hide one in your attic or coal house and you have a theft proof network drive.
This device also comes with Bittorrent, ftp etc capable client and servers, although no podcatcher support which would make it a done deal for me. Bittorrent support may help marketing, but I the main appeal for many is an always on Samba Share - right now I need a (noisy) PC running to share media between my xbmcs (the xbox's SMB server implementation is single threaded and cannot run in parallel with xbmc). Podcast support + SMB server would allow me to part another PC for eBay (I am down to three today); but without both those options I am skipping the ~$270 device for now. By Xmas I predict similar devices will also pull down podcasts and IPTV via RSS.
Before this router appeared I was close to buying another used xbox (~$90 on Craig's list [Aug 2006]) and running a SMB share via linux on one. In case you have not heard; it is now child's place to hack an (original) xbox without a chip/ special game/ memory card etc. A used xbox makes a very cheap linux server or 1080i capable media center. That reminds me I have some used xbox games to sell on eBay... who has time for games anyway?