Either lathe will net you a considerable upgrade. I think another hit it on the spot, PM is 2" less capacity, heavier beast, shorter bed, easier locking headstock, lower overall height (to turner's elbow). I have the Grizz and I am happy. Now if you were talking a 24" PM...... drools.
Robust is in a different class.....American made. I would love one, but that is not justifiable to the family when the Grizz can do the same, ahem....for now.