It really depends on your experience, bike setup, and difficulty of trails you’re trying to ride.
If you want mellow trails with awesome views, lake access, and ride in ride out campground Tsali is probably your place.
DuPont is slightly more challenging, much more exciting, and has a much larger variety of trails. You could spend 2 days at DuPont and not ride everything.
Also, Dupont would be closer to the Pisgah trails which gets really gnarly really fast.
Keep in mind that many of the Pisgah trails really do call for a either a full suspension bike or some serious skills and large cojones. I did Black Mountain on a Stache and was majorly puckered the whole way down.