Well both will do the trick.
Astroplanner out performs Skytools in Custom Catalog loading especially if doing User Catalogues from observing session to observing session. Skytools can do this but is less configurable.
Skytools 3 probably is nicer for Realtime, especially graphically.
Astroplanner is under US$50.
http://www.ilangainc.com/astroplanner/order.shtml
Skytools 3 is US$125 or US$175 for the Pro version.
http://www.skyhound.com/order.html
I personally use Astroplanner far more than ST3, but I do not do realtime.