Comparing SkySafari Pro 4 to Pro 5, there are improvements in the settings. More sounds (atmosphere and chimes?) have been added long with more choices for your horizon. The Search interface has been modernized and is now a narrow column on the left side of the screen instead of taking up the entire screen. The Time tool has been reworked into a smaller bar, but is a little more awkward to use. Two more tools have been added to the tool bar; Tonight (At a Glance) and Share. The Tonight At A Glance opens a narrow column on the right side of the screen providing a summary of what is happening in the sky. It shows information for the Sun, Moon, planets and selected satellites for the evening.
As I said, a great app, but there is a small but annoying glitch when orbiting planets. Pro 4 allows you to zoom out to the limits of the largest orbit for any given planets moons. Pro 5 does not. Jupiter for example will not zoom out far enough to even to include Ios full orbit let alone the full compliment of Jupiter moons. This goes for all planets. I hope that this will be fixed in the next update.
Is it worth it? In spite of this minor but annoying glitch - absolute, specially at the half-off sale price.