For a comparison of SkySafari 5 Pro / Plus / Basic for iOS see here:
http://skysafariastronomy.com/skysafari-5-professional-astronomy-telescope-control-software-for-ios.html
For a comparison of SkySafari 5 Pro / Plus / Basic for Android see here:
http://skysafariastronomy.com/skysafari-5-professional-astronomy-telescope-control-software-for-android.html
For a comparison of SkySafari 5 Pro / Plus / Basic for Mac OS X see here:
http://skysafariastronomy.com/skysafari-5-professional-astronomy-telescope-control-software-for-mac-osx.html
For double star catalogs, how do the Plus and Pro versions compare? I believe Pro includes the full WDS catalog and Plus doesn't -- but how deep is the multiple star catalog in Plus?