Hi Sheri! How exciting to be planning your family's first trip to Disney World!
I'm a big fan of Disney's deluxe resorts, so you can probably guess what I'm going to say: Yes! The Polynesian is worth the extra money! I've stayed at both the Polynesian and the Port Orleans, and in my opinion, your family of 5 would be more comfortable at the Polynesian. The Port Orleans Riverside has rustic-themed rooms in a tranquil setting, but the tropical-themed rooms at the Polynesian are much larger, which would give your family more space to spread out. With your young sons, I bet you'll be spending lots of time at the Magic Kingdom park, and the convenience of being able to hop on the monorail and go into and out of the park in a few short minutes is priceless. Furthermore, you'll have some of the best restaurants at Disney World within easy reach from the Polynesian. They Polynesian has one of my favorite restaurants, 'Ohana, as well as the Kona Cafe, and you'll be able to ride the monorail or boat to the restaurants at the Magic Kingdom as well as those in the Contemporary, Grand Floridian, and the Wilderness Lodge. You'll be able to watch the Magic Kingdom fireworks and the Electric Water Pageant from the Polynesian, and your children will have a ball splashing in the volcano pool. These extra amenities and conveniences are worth the extra cost in my opinion. Keep an eye on the
Special Offers page on the Disney World website; you'll often find deals there that enable you to enjoy the deluxe side of Disney at a discount!