We have been going to HH for 30 years now and our first 18 years were spent renting condos and homes at Sea Pines. Since we purchased at the
DVC resort in 1995 (it didn't open until 1996), we have not stayed in Sea Pines and have even now purchased a condo within sight of the DVC resort because we love the area so much.
Sea Pines does have some beachfront areas and many, many condos/homes within 200 yards of the Atlantic. It is a wonderful area, with some historical sites, stables, shopping, dining, tennis and golf within it's boundaries. Sea Pines is a gated community and we always felt very safe with our children there. There are miles of paved bike paths throughout the Plantation. I would highly recommend the area.
We have also enjoyed the Palmetto Dunes area where the Disney resort is located. The resort is not on the beach - it is centered on it's own private and gated island within Broad Creek, a tidal marsh teeming with wildlife. We have enjoyed watching dolphin, sea otter, osprey, alligators and even manatee right from the DVC resort. The same island also forms a boundary of Shelter Cove Harbour with a marina and lots of water-based activities like kayaking, tubing, parasailing, dolphin tours, eco-tours, shelling, fishing and about any type of water related activity. The HH beaches are wonderful - with a very gentle slope and minimal rip currents. At low tide, the beach is about 75 - 100 yards wide - about 25 yards at high tide. The Disney resort is located about a mile from the resort and can easily be reached on foot, by bike (can be rented at the resort or many other locations) and by vehicle. Resort guests will have a permit providing access to the beach thru the guard gate and the resort also provides a free shuttle to/from the Disney Beach House - which has it's own pool (in addition to the one at the resort) and snack bar (in season). Both pools are heated and can be enjoyed year-round. The staff at the Disney resort is top-notch and are truly devoted to providing a quality experience for every guest.
There are seven restaurants within walking distance of the Disney resort and many others a short drive away. There is also a mall, grocery and more restaurants about 1/4 mile away in the Shelter Cove area.
As for deciding which is better - I don't think you can go wrong with either location. HH is a wonderful family destination with lots of activities available year round.
Enjoy!
