They definitely stand out (not that I'm much of a judge of covers).
A few details that may or may not be relevant.
The styling of your name is inconsistent. I prefer the font and yellow of #1, though the size feels wrong (too large). Also, the specific yellow doesn't quite match the other lettering (this may be because of the metalic effect elsewhere).
I see what you're doing with the pendant and the book numbers, but I don't beleive said numbers are required. Indeed, many may not even notice them. As such, the straightness of the pendant placement feels slightly contrived. (That it hooks the C in voice is a nice touch., though)
The presence of the moon (#1) and sun (#3) somewhat hide the "when" in the series title (contrast issue).
The Poseidon shadow on #1 feels like a cardboard cutout, this probably because it's been skewed. I assume it's due an upgrade per the sppoky face on #2.
Overall, the Aegis cover, with its star/planet as the dominant feature, suggests more SF than the myth/drama I believe you're aiming for.
For #3, I'd be inclined to keep the figure as having ancient accoutrements; it reinforces the mythelogical theming.