Doc is a character that I never really cared too much about when I was little, but has grown on me in later years, for a couple of reasons.
First, the realization that Doc is kind of the Donatello of the Joe team. In the cartoon, when the Joes needed an intelligent or scientific solution to a problem, their only choice was to go to Doc. Even though he was a doctor, not a scientist, I guess he was the only smart guy they had.
Also, while I *do* like Lifeline, I think the way Doc's pacifism was handled in the early Marvel comics run was better than how they treated Lifeline. Doc managed to disarm Destro with a snowball and get a serum from him by basically tackling him and letting Destro pummel him. That's pretty ballsy against a guy with a polished beryllium steel head.
For Doc, I was looking for two main feature: glasses and a sort of doctorly looking outfit. I looked at a few others but decided the Heroclix Lucious Fox mini had a good pose for the Joe's resident smart guy.
It's a pretty good match, although a little more formal than his normal uniform. He looks like he's about to make the rounds at the G.I.Joe hospital.
Hope the prognosis is good!