I moved from Woodbury, CT down here two years ago. The area has undergone significant changes in the last 15 years or so. The big banks have contributed a lot to the culture change. I live in a subdivision in western Union County and 90% of the families are from the north. We chose this area because of schools, taxes and atmosphere. The negatives in SC are education and more rednecks but taxes (real estate, income and corporate) are lower and real estate is more affordable but compared to CT you can live like a king in NC as well. Gas is cheaper in SC as well and we all go there to buy our fireworks too. You're going to be amazed how much lower your utility bills are going to be. Indian Land, Clover, Rock Hill and Fort Mill are some places in SC you could consider but after looking we decided to stay north of the border. Oh, and if your kids go to college, the public system is a great deal in NC. It's about $18K for Chapel Hill and residents get very preferential acceptance.
We were warned by several friends from the area to avoid the Charlotte Mecklenburg School System. The schools can be hit and miss with lots of redistricting and other headaches. Check out the ratings for schools in Marvin, Weddington and Wesley Chapel, they are all in the top few percent for the state and have lowest school crime rates. Even at the better schools in CMS the crime is much higher. Again, the taxes are considerably lower in Union County and many are fleeing south out of Charlotte/Mecklenburg County.
Some of the choice may depend on where you have to drive for work each day. There are some nice areas up on Lake Norman as well but the schools aren't quite as good and if you have to commute in and out of Charlotte each day the traffic is murder.
South Park/Meyers Park are very nice if you can afford it and you enjoy living in a city. If you don't like congestion etc. I would consider western Union County (Eastern Union County ie: Monroe, not so good).