The main reason you'd want to use all caps is to create minimal, even leading (the space between lines.) It makes the speech look neater, and fits nicer into the speech bubble-makes things easier for the artist.

The main reason you'd want to avoid all caps is modern message technology has caused people to automatically assume it means yelling, something past comic artists didn't have to worry about when establishing type standards.

Whichever you choose, stick with it. Flip-flopping will just confuse readers.

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In some of us a thin person is struggling to get out--but they can usually be sedated with Chocolate Cake.

ah, guess i should have explained it better, i meant capitalize as in using grammatically-correct capitalization at the beginning of sentences and such. someone suggested it the other day, but no one has ever seemed to mind that i don't, so i thought i should find out for sure.

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Mill City Fiasco - powered by pure glee. | PONIES!

Ah. Well, being grammatically correct in comics is what I prefer, but all kinds of typographic styles for comics are being invented and used.

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In some of us a thin person is struggling to get out--but they can usually be sedated with Chocolate Cake.

I vote to maintain the status quo.

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Signatures are scary!