I’m finishing up reading Edward Tufte’s canonical The Visual Display of Quantitative Information and the following quote about typography seemed relevant for your decision to use capital letters for the menu headers in VS 2012:
With regard to typography, Josef Albers writes: “The concept that ‘the simpler the form of a letter the simpler its reading’ was an obsession of beginning constructivism. It became something like a dogma, and is still followed by ‘modernistic’ typographers.… Ophthalmology has disclosed that the more the letters are differentiated from each other, the easier is the reading. Without going into comparisons and details, it should be realized that words consisting of only capital letters present the most difficult reading — because of their equal height, equal volume, and, with most, their equal width. When comparing serif letters with sans-serif, the latter provide an uneasy reading. The fashionable preference for sans-serif in text shows neither historical nor practical competence.“ Josef Albers, Interaction of Color (New Haven, 1963, revised edition 1975), p. 4.