Compositionally, I think the first one is stronger than the second one. On the second one, the more distant shuttlecraft seems to fit too neatly into the frame of the interconnecting dorsal structure of the starship, especially as the tonal values between ship and shuttle are closer. They way everything overlaps in the first one, and the more familiar angle on the ships, gives a sense of pushing forward, but, somehow being right underneath them seems more static, at least to my eye.
As a weird technical aside, it's strange to see shuttles in flight with their landing gear still down.
And I note that there are two red stripes on the structure surrounding the planetary sensor dome on the starship in the second image, but not the first.
Anyhow, the actual models look great and the rendering is beautiful in both images. Great work! I'd love to see more. You should post more often!
--Alex