We stayed at Landsmark Resort a few years ago and found the rooms to be musty and old.

The water park and lazy river was okay. However, it is smack in the middle of a busy beach area and you have to park across the street unless you happen to get one of the few spaces to the side of the building.
The last few years we have ventured just south of Myrtle Beach to Pawley's Island. We stay at the Litchfield Beach and Resort Club.
They have lots of different options for rooms. We actually stayed in a four bedroom condo (shared it with my brother and his family). The condo was beautiful with a full kitchen (granite, etc), dining area, family room, four large bedrooms, four bathrooms, and a washer and dryer. We rented it for $800.00 for the week (ended up being 400 for each family).

They also have one and two bedroom condos too. Our condo was not on the beach - it was next to the golf course so that it why the price was a great deal. We didn't mind since we kept all the beach gear in our car and just drove literally across the street and around a few condos to the resorts beach house and parking area. The beach access there is just for guests. They do have homes and condos that are oceanfront, and oceanview as well.
The resort has a large swimming pool with a lazy river and separate kid's pool with dumping buckets, etc. The beach is right there and not particularily crowded - this was at the height of summer the last week of June leading into the fourth of July holiday. You can also rent bikes to use for a day or your entire stay.
There is a Piggly Wiggly (large grocery store chain in the south) across the street and serveral restaurants to choose from besides the few at the resort itself. The resort has at least one nice sit down restaurant and then Starbucks and other things. There are lots of great local seafood places and even Subway to try if you want just outside the resort complex. It is definitely family oriented. It is quite a ways from all the Myrtle Beach proper action but that is what we like about it. It is much more tropical and relaxing with no huge hotels and crowds to deal with.
www.litchfieldbeach.com is the website.