I just heard that commerical for the first time the other day. I have Sirius so I get to hear all sorts of odd ball kinds of commercials and non of the revelant local one LoL.
Anyway, No, I've never tried it, nor do I know anyone who has. Honestly I am of the frame of mind that a vitamin or supplement probably isn't going to make the huge changes they claim on the radio if you're already feeding a high quality diet. If you're feeding 'ol roy then maybe it would... ?
I'm on my last bit of seameal for Jazz and I'm not going to get another tub of it unless I wwant to use it on my tibbies. It doesn't seem to be having any great effect on her and she could do without it now that she isn't eating pedigree (previous owner) anymore.
What I really DO like though is Prozyme, it's good stuff and unlocks some of the nutrients in your dog food that would otherwise be unavailable to your dog. I noticed a difference in my dogs right away when I first started using it years ago. They all put on weight like crazy and we were able to back off the amount of food they were eating without them missing it or droping weight. It was great. I know they make other brands of enzyme supplements too, to my knowledge they all work the same though some have different types of enzymes and other stuff added. It's the only thing I add to every single dog's food all the time.