I tend not to judge the quality of someone's advice by how they look, though. It's a fairly poor indicator in my opinion. I've met people who are incredibly more knowledgable than myself, yet maybe aren't so big, and some people with amazing physiques who have no idea what they're talking about. I always think of Arthur Jones old spiel, which goes something like:
"Find the biggest guy in your gym. Follow him around, taking copious notes on everything he says and does. Then do the exact opposite." Genetics will trump knowledge every time.