Any "Master" certification program indicates that you've done some learning, celebrates that, but counter to the name of the program, reminds you that you have a lifetime of learning ahead of you. The EAS program consists of 4 exams - field, oral, lab and written - and by the end of it last summer, I was overwhelmed with the variety of information sought and humbled knowing in how much more detail the exams could have gone.
I think the primary benefit is to provide credibility - esp. among people who don't know you or your beekeeping. As an example, we are seeing a rise in intermediate bee schools in this part of the country. I for one, am suspicious of intermediate schools that are not taught by a Master Beekeeper. Then again, I take time to check out the teachers - some very good beekeepers see no value in the MB programs - but they are still very good beekeepers.
I passed 3 of the 4 MB exams last summer and will retake the one that got away from me this summer.
The MB program works for me - my wife has the skills to be a Master Knitter but has elected not to go down that path. I completed the Master Gardener program this spring; in part because I am curious about bee forage, have a veg. garden for my family, and appreciate the educational programs put together by Cooperative Extension.