I just tried Luna for the first time, on a MacBook Air. For me the colors and the contrast in LunaStudio was a disaster. I have also lost sight of the initial tutorial, maybe because I did some sort of upgrade.
It also seems that LunaStudio/Atom uses quite a bit of CPU, as the Mac-fan got turned on now and then.
The written Luna language looks quite promising (I downloaded the readable PDF book), but as long as LunaStudio is based on Atom, I will be reluctant to use LunaStudio on my MacBook Air.