I agree with the other posters that Hilton Head, Kiawah, etc. are nicer places: more back-to-nature, less flash, more family-oriented. Myrtle Beach does have a carnival, wild, anything goes atmosphere. Myrtle Beach is big, busy, and it's about shopping, drinking, eating out, playing golf, and spending money. Myrtle Beach's nickname is The Redneck Riviera, and it's not a place to allow teenaged boys to run around alone.
However, you need to realize that Myrtle Beach itself is actually a very small spot, and few people actually stay there. If you move north or south (to the so-creatively named North Myrtle or South Myrtle Beaches), you'll find quieter, more family-oriented places. I'll suggest three, which are all quite different:
Marriott Grand Dunes -- bring your wallet because it's not cheap -- this is a full-scale ocean-front Marriott with a hotel and condos. The pools are probably the nicest in the Myrtle Beach area: Two very large pools with modern, fancy styling. A water slide and two hot tubs. The pools are also very crowded! Very expensive drinks, ice cream shop. For an extra fee, you can rent luxurious double-person loungers, but they're not next to the pool. They also have hammocks. The condos next door have a separate pool, though it's not so fancy. The beach is a little narrow, but it's quiet. We stayed in the hotel section once, and although it's lovely, it's over-priced and we probably won't go back. It's just hard to justify those prices.
Grand Atlantic Ocean Resort -- this place is much more affordable -- lacking the fancy lobby and squeaky-new feel of the Marriott, it's a great value for the money. Do not read that as "run down"; everything is nice, just not in a flashy way. Every unit is a condo with a kitchen and an oceanfront balcony. Stack-up laundry facilities in every condo. It has two nice-but-basic pools (one covered, one out in the sun), a kiddie pool, and a lazy river. It's right on a nice, quiet, wide beach. It also has a sandwich, pizza, and ice cream shop with good prices on the first floor. There's a grocery store nearby, as well as restaurants. We went there first with friends, and now everyone in "our group" stays there.
Myrtle Beach State Park cabins -- this place is very affordable (I think we paid $500 for 4 nights in a three-bedroom/two-bath), but they only have five cabins (and two apartments), so getting reservations for prime times is hard; you have to call as soon as the 11-month calendar opens up its dates. Don't think summer camp cabins with wire mesh screens; these cabins have huge screened front porches, hardwood floors, nice furniture, and cable TV. The kitchens are a bit small, but they're fully furnished. You can see the actual cabins online. This place has no pool, but the beach is wide and lovely, and you practically have it to yourself. You'll have to pack your own beach towels here, though bed linens and kitchen linens are included. Laundry is available down by the camp store, in the campground. The fishing pier is very nice, and you can walk to it from the cabins. Lots of nice walking trails and a boardwalk. This is fairly far from Myrtle Beach itself, so you'd expect to drive more from this location, though there's a Food Lion and other stores right outside the park.
