I have read with interest the various above comments about price, materials and quality and have to say that in my experience a low price tag does not mean low quality.
Some years ago I bought an Electra Beckum planer. They are now part of Metabo, but still sell the same unit -
this one
Althought it has an alloy bed which is removed as opposed to being tilted to access thickness mode, the fence is 100%.
It is made from aluminium extrusion, but the design of the profile is such that the face is perfectly flat, and is at right angles to the edge, so as long as the edge is flat on the table the fence is a perfect right angle to the bed.
Having read this thread I thought I may have just been lucky, so I contacted a few other folks I know who have the same unit, and theirs are the same.
I also have a number of other tools and accessories made from alloy or aluminium which are just as accurate
So if Electa could design and manufacture a unit at half the price of the Jet one, I can't see why the Jet engineers can't come up with a more accurate fence without any increase in cost (apart for the charge for retooling a new extrusion mould).