We are new to this having picked up our first trailer in April, but struggled with this same question. We went back and forth between the Shadow Cruiser 280QBS and the 282BHS; finally settling on the 280QBS.
http://www.cruiserrv.com/products-2015/shadow-cruiser-2015/floor-plans-shadow-cruiser
282BHS positives were the additional slide (making room for the island) and the bathroom layout with additional entry door. Ultimately the wife gave up her island kitchen so the kids could have their own room and the extra dinette is great for the kids (3 total; one boy and two girls) to play games, color, etc.
Storage is decent as there is plenty of room for the kids stuff in their room and we have utilized the space under the sofa via plastic totes. The dinette does not have drawers to easily access the space under the seating, but will probably work a DIY solution after this first season.
We really liked the Fun Finder 299KIQB, but was afraid of weight and overloading our 2015 Yukon XL
http://www.cruiserrv.com/products-2015/fun-finder/floor-plans/item/f-299kiqb-2015