I gave my Elgato turbo.264 HD a real test today, encoding an entire season of Doctor Who from the native MPEG2 Eyetv recordings I made from BBC One on Freeview into h.264 iPhone Quicktime movies.
Thirteen episodes took just over two hours, about four times faster than realtime. Each episode was taking under ten minutes to convert. The turbo.264 HD software then automatically added the episodes to iTunes which is useful (and not useful).
I am impressed with the turbo.264 HD and recommend it.