The SC DMV offices I've been to are very efficiently run, in my opinion. The longest part is the line, but all things considered it moves pretty well.
They have a lady at the door who finds out what you're there for, lets you know exactly what it is you need to have with you, gets you started on all the forms required, and gives you a number tab. Most times I've been to the SC DMV, I'm being called not long after I finish whatever forms needed filling out.
When given the chance, I like to show up early when they open, too, just because.