Both are beachfront, and just a few blocks from each other. I stayed at Anderson last summer, but toured Ocean 22. Anderson's pool and "lazy river" are pretty lame. Ocean22 has a bustling pool scene, more modern decor/design, and better on-site amenities. There's a Starbucks at Anderson, but Ocean22 has a "marketplace," if I recall correctly.
As for what there is to do in Myrtle Beach--well, you can go to the beach. You can go deep sea fishing. You can go golfing. There are outlet malls. Many seafood buffets, and even more pancake houses. I think you can find shows and concerts and more cookie-cutter tourist things. If you're looking for an authentic, unique and transformative vacation, Myrtle Beach may not be for you. But if you want a gorgeous beach, a top-drawer property, and good food (all of which is also affordable), Myrtle Beach definitely works.