I've used ShadowScript as my primary teleprompter software for over 50 live concerts in front of crowds of 20,000+ and would recommend this to anyone who needs a professional teleprompter solution. The program runs exceptionally well in action with no noticeable flaws, pauses, glitches or interruptions on my MacBookPro. On the fly changes are easy to do without the performer seeing the editors' window or setlist changes(huge plus). The only reason I didn't give it 5 starts is because it feels like it was designed for a PC in the sense that it doesn't give the user the sleek design of the Mac experience. Overall this program is great and is well worth it for its' price. It has never let me down and I would recommend this for anyone who needs a teleprompter.