Have both The Sky Professional version 6 and Starry Nights Pro 5 but prefer The Sky Pro 6 mainly due to it not being as resource hungry as Starry Nights (does not require Open GL or bogs down slower CPU's) and due to some features not present in Starry Nights .
Both excellent programs though.
Also used Cartes du Ciel quite a while back , good enough for the price
but lacks the features of the other 2.
You get what you pay for.
