Have used GPSNavX on my Pismo and PPC G5 20", this is the only navigational software to use on your boat. Easy to use and set up, with very fast e-mail troubleshooting and question answering from developer. Best of all you can't beat the price. The average boater will never use all the features of Nobletec, and the price, wow! GPSNavX kicks Nobletec's butt. Yes Nobletec is a PC software but now that you can use it on your Intel Mac, why would you. When your PC boating buddy cries about the constant crashing, just laugh or tell him to switch to a Mac with GPSNavX.