I don't know the Abu line of spinning reels, but in general it seems that as they get more expensive they use lightweight material like magnesium for the frames, more bearings as you mention, and better overall machining. You should get a lighter, smoother reel that feels well put together. Hard to make comparisons unless you can get your hands on one to try out.
Cabelas has Pflueger Patriarchs on sale in the bargain cave for $129. They usually retail for around $200. Never have fished one, but I have a couple of lesser Pfluegers (Supremes) which I am relatively happy with, except that the drag clicker is a cheap little metal stud mounted on the spool that wears out after a while. I would hope the Patriarch has a more robust clicker, but you never know.
I also believe the Patriarch comes with a spare spool, which there days a lot of spinning reels do not.