Last Christmas on our way south I used US-17 from Wilmington all the way down to where it rejoins I-95 with the exception of a segment along the Grand Strand where I opted for SC-31. I agree with froggie, the segment from I-95 to Charleston is a very good road now and there's no reason to avoid it, although I would advise driving with caution if you go through at night because it's extremely rural and extremely dark, the sort of road on which I worry about deer appearing out of nowhere.
We went through there perhaps two years earlier when we were coming down I-26 and a huge wreck on I-95 caused me to continue on I-26 to Charleston and then loop back on Route 17. At the time, it was still two lanes and under construction. The relatively fast completion of the project coupled with the road's transformation was quite impressive.
In case you are unaware of it, the town of Ridgeland located along I-95 south of where 17 bears off towards the coast is a notorious speedtrap. Don't exceed the speed limit within Ridgeland's town limits. On one trip north, we saw a cop standing on an overpass with a radar gun and a radio, and shortly afterwards there were six town cruisers parked along the shoulders ready to pull over anyone and everyone. I tend to try to hold 68 mph through there just as a hedge against speedometer error.