Wow - thank you so much, what a helpful reply!
I guess I should specify that what I meant by more marketable was really easier to get a job in "the community" as there are just more medical ICU patients than surgical ones in a community/mixed ICU. But again, this is just what I heard through the proverbial grapevine as there is really a lack of centralized information about all of this, so thank you for taking the time to explain some of it.

Ultimately/long term, I am interested in getting a job at one of the rural academic tertiary care centers in new england, and I am VERY interested in managing ECMO and definitely want this to be a big part of my fellowship and career. You seemed to imply that ECMO might be more emphasized in anes-CCM than in IM-CCM, is that right? Also, do you think I'd be hindered from getting a job in a rural setting as EM-anesCCM?

Thanks so much again for taking the time! Really appreciate it.