the byrd follow the curve of the head pretty much. the cutters also
have a
curve. that would make them cut cleaner. overall the quality I bet is
10 times
better and does not cost much more.

I guess it would be a slicing action since the knives are at an angle.
So are these cutters indexed or is there some sort of alignment tool?

I like the idea of buying the cutter head separately. You could start
out with a normal planer or jointer, then upgrade later.

brian