I've worked on shoots with the likes of Kate Moss, Vogue, Vogue Italia, ID, Josh Olins, Miles Aldridge, Liz Collins and many more. But I wanted to be the one taking the pics, so I went it alone earlier than most assistants. However, it seems rare that people even bother to assist any more.
I personally learned a priceless amount assisting, which now means I can teach my assistants, rather than rely on them like many photographers I have witnessed.
As far as I'm concerned, it is too early to consider anything that's happened a career maker yet. Hopefully in 5 years time I will be able to answer that one better. As for setbacks, I dont believe in them. Everything is a learning experience. No matter how bad things get, something can be learned from it.