As far as I understand, at the time of being passed over to Prolific for download from SereneScreen, the two versions are virtually identical.
From SereneScreen you will get the addition of an installer, the statistics default to off, and it never expires. - But it's rarely the latest!
With the Betas from Fish-Byte, the statistics default to on, and they expire every few weeks. -
BUT YOU ALWAYS HAVE THE VERY LATEST! 
(..... plus you can 'install' it yourself if you wish.)
I cannot think of a good reason
NOT to use Jim's very latest version from...
http://www.fish-byte.com/MA3Beta.zip 