I have a slr-zoom model of the gorilla pod. Last year, while visiting NYC, I wen to B&H Photo to buy a ballhead joint for it. The salesperson asked me what I was going to use it for and I pulled out the Gorillapod and my Rebel XT (with 17-40 mm L lens). He didn't want to sell me the ballhead. The guy said he'd sell me the ballhead BUT he would put something in the computer that said that he advised me NOT to buy it. Well, that put me off the ballhead. I left without it.
Since then, I bought a SLIK tripod that happens to have a removal ball joint. If I really want to, I can detach it and put it on my Gorilla pod but I've never done and I manage to muddle through by playing with the legs.
I like the Gorilla pod and have used it in situations where I needed a second tripod. I try to still have the strap around my neck when using it though. I now have a Canon 40D and I haven't used it with the Gorilla pod yet so I'm hoping it'll support the weight.