I've been very happy with my bench, I built it following the EAA plans almost exactly, except for the following:
(1) I lengthened the bench to 8 feet.
(2) I made the top surface larger than the frame to provide an overhang all around the bench for clamping. My overhang is 1.25 inches all around, but if I were to change anything, I would have made the overhang 1.5 inches; the 1.25 inch overhang works, but it's just a bit too small when reaching under to tighten the clamps. I've found the overhang to be very, very useful.
(3) I used MDF for the top surface. I don't know exactly what MDF is, but it looks like a highly compressed mixture of sawdust and glue. It's very hard, flat, and smooth, and has worked very well.
Good Luck!
John