I have the Focus, and just used it a few times on our recent vacation - it did a good job of holding up a gripped 5D II + 24-70L + 580EX II while being used on the ground in a standard tripod setup.
When testing prior to the trip, I tried the same equipment with the GorillaPod hanging on to some railing (camera hanging directly off the side), and the Joby Ballhead X was not strong enough to keep everything in place, so some of the more unusual placements that are possible with the GorillaPod may not work out with that head if you're using heavier lenses.