There is a better solution, at least in terms of legibility, perhaps not so much aesthetically. And I'm 99% sure you've already seen it.
Black border, white letters.
White letters are almost always brighter than the background, and the black outlines act as a sort of shadow, separating the text from the background.
Of course, the best legibility is still achieved by controlling the background; so adding a flat colour backdrop.
Both of these solutions, however, require the use of 2 colors, so this might not be the answer you're looking for, due to it being more complex and likely more expensive.