Private student loan rates are lower than non-specialized private loans (e.g. "signature" loans) but slightly higher than government loan rates. That may be changing, as pending legislation would raise government student loan rates to similar rates as private student loans.
Most private loan programs are tied to one or more financial indexes, such as the Wall Street Journal Prime rate or the BBA LIBOR rate, plus an overhead charge. Because private loans are based on the credit history of the applicant, the overhead charge will vary. Students and families with excellent credit will generally receive lower rates and smaller loan origination fees than those with less than perfect credit. Beginning a few years ago, money paid toward interest is now tax deductible.