A crappy job of cutting????  Have you used one??   No a Macdon won't cut between hilled potato rows, but I wouldn't say it does a crappy job of cutting.
If they did a demo where they had a wide arced field ridge the Macdon would hands down beat the Deere.  The Deere would only be able to cut a strip down the center.  Its all in how you set up a demo.
And I am not trying to bash Deere, they are trying, and when Deere comes out with their hinged wing draper you'll think it is the best thing EVER.