Is there any way that you could rephrase this question. I'm not sure I understand what you mean by 'responsibilities'. I don't mean to start a flame war, but have you ever thought about the fact that there is usually much more job security with the majors. A large and established airline is much more likely to remain afloat than is a small start-up. The most important thing on the mind of a pilot when getting a job is one of 2 things (especially when young); Career potential, and security. Well, that is what the majors offer.
Not to criticize the job or anything, but being a commercial airline pilot is not exactly the best thing in the world. Many are away from their families for days at a time, the training is extremely intense, not to mention pressure. Most pilots want to get on with a major, start a career, and earn enough money to retire well. Lets put it this way...you're a software designer, striaght out of college. Who would you rather work for, Microsoft or some no-frills start-up which might not survive the next quarter. I'd pick Microsoft (just an example) so I could build a career.
Sorry for the WOB