Dan, what you like--the ratcheting mechanism--is what threw me off on the Digger. Having been frustrated as all-get-out (!), the last thing I wanted was more mechanical pieces (indeed, also one of the reasons why the tester in the video below chose the anchor he did).
That being said, in the end all that matters is that the captain is comfortable with his tools, and it sounds like all the ones mentioned (Mantus, Digger, Box, Fortress) are good performers.
I had a few moments, so here are two of the sources I checked out when making my decision (for the super-nerdy!):
http://www.petersmith.net.nz/boat-an...ce-testing.php and
https://www.youtube.com/watch?v=l59f-OjWoq0.
Cheers!