Preferred has two booking categories, boardwalk view and pool/garden view. Boardwalk view (about 15% of all rooms) is the best view at WDW. Pool/garden (about 67% of all rooms) is a mixed bag which can run from very good to truly mediocre and are often just a tad above standard view. Standard view (about 18% of all rooms) is actually fairly good as you see a lot of grass and trees before any road and part of the standard views see a canal and Studios.
Boardwalk view is more than worth the extra points. Pool/garden is questionable as being worth the extra points. Note that standard and boardwalk view can be difficult to get at 7 months out.