Slightly easier from the Met line platforms - if you're in the fourth car (heading north) you should come out roughly by the steps to the intermediate concourse.
Otherwise from the C&H car 5 towards the middle or car 2 towards the middle, steps up and over to the Met platforms then the same - stairs to intermediate concourse then escalators down to platform level.
However, I concur that if your final destination is Marylebone (or nearby) then you're just as well walking from Baker Street rather than changing, as it's a reasonable distance (and a lot of stairs) below ground at both stations. I wouldn't recommend walking to Marylebone if you're travelling onwards by Tube, though.