The beta has a display on the unit, is very compact, and from my original research found that people had better accuracy and results with no issues with this unit. If wanted, a printer can be added to the beta (and the master)
The F1 has a wired display that can be set on your bench, so you can see your value at three feet versus 10 feet. I did not see the issue of reading the display from 10 feet, and if it was a problem, I could get up and walk to the unit. The F1 also allows for a few more functions, but all I wanted and needed was the value of each velocity of each shot.
The Master is the same as the Beta, execpt it offeres a little more in memory and functions and as stated above it allows the attachment of a printer.
Why I bought the Beta:
No wires to break or tangle. Unit very compact. Had best score and reviews online. Was said to be most accurate. Had fewest complaints or problems.
The unit I have for sale is brand new and has never even had a battery installed (9V) I think. If you are interested in buying it, please let me know.