I've always had very mixed feelings when it comes to collaborations, mainly because I've rarely had what I could call a good experience--let alone a good result--when I've collaborated in the past.
I have a friend who would really like to have me work with him on his graphic novel project, and I'm...resisting...'cause I've been down this road before.
Several years ago, I met a writer who looking for an artist to do the "graphic" portion of a graphic novel he'd written. We met, and I liked his ideas for the story, so I started designing characters, working on the basic layout of the book, and creating some finished drawings, using a copy of his script as a guide.
The next time we met, he had re-written some of the portions of the story that I had already illustrated, and most of my finished layouts, and some of the finished drawings, were now basically useless.
Over the next few months, every time we met, he had made signifcant changes to the story, and I increasingly felt that I was wasting my time working on his project--instead of my own stuff--only to find out that this design, or that character, or that section of the story, had been "cut".
I finally quit the project.
Now I know that there are collborations that "work", and artists who work very well together.
But, for whatever reason, I'm not one of those folks.