I use both — Title case for short headlines, sentence case for sentences.

To me, the consideration is readability. And readability is function of your brain telling you, “I can read this,” or “Find something better to do with your time.”

Generally speaking, capital letters disrupt readability. In typesetting a book, for example, the correct protocol is to reduce the point size of acronyms by 2 points so that the grouping of letters placed in a sentence is not a roadblock to reading. The smaller caps are closer to the x-height of the lower case and thus easier to scan, read, and understand. We DO read by shapes. If ALL caps are used, all word shapes become rectangles and the brain has to go back and insert lower case letters (your brain’s default created when you first learned to read) so it can make sense out of what it’s seeing.

If YOUR brain learned to read using capitalized nouns (German), then it will read them easily; if it did not, it won’t. Capitalized will be the default against which your brain will judge what it sees.

As a graphic designer, it is my rule that my “art” should never get in the way of readability. If it does, then it’s bad design. It isn’t simply what I like or feel like doing, it’s what will make this the easiest to read and thus understand. When case gets in the way, get rid of it.