Looking at the diagram on their web page, this looks to be a single arm length equivalent of the Feickert.
What an arc gives you over either this or the Feickert is the ability to magnify your view of the effective length/pivot-spindle combination - by swinging the stylus over the length of the arc. Smaller errors are more easily seen on an arc protractor.
Having said that, there are a few individuals who claim on this forum that they achieve an equal level of precision with a Feickert and an arc protractor like the MintLP.
I consider this more a testimony to their skill and fastidious approach than to the superiority of the Feickert over any arc protractor.
If pressed to make a recommendation, it would be for an arc protractor. If you're pressed for cash, someone posted a link a while back to a free Windows application to make your own arc protractor. It will get you most of the way to a MintLP. Buy card stock paper for your laser printer.
Thom @ Galibier