Both are really cool, but Sleep I find to be the one I like by alot more. It's really relaxing and sets a good mood, and basically just does what music is set out to do. Flight is also good, and does the same when it comes to setting a mood and imagery, but put next to the other, it just doesn't have as much going on and isn't quite as adventurous, which isn't taking points away from it. It's still great, but I find the other one a bit fresher. Definitely keep it up.