You've hit upon the classic 'recommender' dilemma. Most applicants do not have the kind of access to senior managers that will yield them comprehensive, colourful stories that admissions committees are looking for. Since that certainly sounds the case for you, I would go with your current recommenders. Far better to have someone write a good recommendation, than write a sparce one with little content that does nothing to help your case.
All else being equal, however, (and it seldom is), choose the more senior one, because he will be able to comment on your growth and potential as a leader and manager, in comparison to the many others he has seen during the course of his longer career. Again, though, you will also need to balance choosing someone senior with the fact that admissions committees know that someone say at a CEO level will probably only have time to write a short recommendation for you (again, this shows that all else is seldom equal). This may potentially be less useful than a detailed, example-filled recommendation.