A:
The Slingbox 500 has all the same functionality as the M1 and has the following additional features:
•SB500 can be setup from your TV screen using the included remote.
•SB500 has HMDI passthrough connections and M1 only has Component.
•SB500 has media functionality for viewing, storing, and streaming photos and videos from your smartphone or tablet to your TV over LAN.
•SB500 has a USB connection that is used to stream movies and media over WAN from an external harddrive to your laptop/smartphone via Slingplayer and Slingplayer Mobile.
•SB500 has Blockbuster Online and Dish World apps available viewing on your home TV.