SkySafari has been my one and only astro app for years. For Mac OSX, it is by far the best value for dollar. It blows other apps, costing literally hundreds of dollars more, out of the water. It has a beautiful and functional interface. The OSX and iOS versions complement each other well. As another reviewer mentioned, I use the OSX version for planning and post observation information. I use the iOs version with their SkyFi WiFi module and my iPad to control my goto Celestron scope. The combination allows quick movements to new objects, so we spend a lot more time looking instead of searching. Evenings are much more productive. The OSX version can also control the scope, but a laptop is a bit more cumbersome than an iPad. Not the app’s problem!
But the best part is the unsurpassed support by the Simulation Curriculum staff. They are very active in responding to problems and are continually updating and improving the program. Their regular updates are partly the reason reviews for the current version are sparse.
I heartily recommend this leader, par excellence, of astronomy apps.