I feel like Sky Sailing is more... sincere than Owl City. I like Owl City more because the naive optimism and the general feeling and the synths makes me just love Owl City so much. But Sky Sailing feels more like the more adult side of Adam Young, in some way. Owl City is the "never going to grow up"-band that defines him, but this is the project that gives him the chance of writing something that isn't veiled in extremely fluffy-puffy metaphors.
Might just be me though.