I'm watching it; I think I've got version 6.1 and I'm keen to update the maps.
I assume you've already used this one and upgraded; I read somewhere that there's a code which can only be used once, but I can't see how that could work unless it's "COMAND Online"? - The only other worry is whether I could make the jump without having to install version 10 (?) first.
Last year I took my 2006 CLK from version 4.0 to version 15 without any problems. I think the v15 disk applies a firmware update before going on to update the maps.
I did make sure the new disk was a genuine MB one, and as recommended in a earlier thread, connected a battery charger for the update. You don't want to run out of power during the firmware update.