> Which situation is more correct?

Both the sentences are correct, and how you use the colon is correct in both the cases.

The colon is used to introduce something that explains or expands upon the part of the sentence it immediately follows.
In other words, what comes after a colon delivers on the promise set up by what comes before it.

> All of which brings up to a point: How does one know when it's right to capitalize the first word of a clause immediately following a colon?—_Comma Sense_, Richard Lederer and John Shore.