Stratus III has a larger amp; 100 watts instead of 60 in the II. The controls for setting the cut off frequency to integrate the sub is more advanced on the III. The III is available in real wood veneers. The II came only in Black. There was a III listed hear yesterday. Probably gone by now. Call Ambrosia Audio in LA www.ambrosia.com; They will ship. Ask for Mike Smith, but anyone will do. They recently offered me a brand new III in Black for $1050. List is $1300+ for black. Wood veneer is $1500.
If you go to www.rel.net and view the listing for the Stratus III by right mouse clicking and opening it by itself in a separate window without the left menu; then in the address bar at the top of your browser change the III in the address to II; hit return; the info on the Stratus II is still on their webserver.