Check out Pros and Cons of Private vs Government Student loans

Requires a Co-Signer

Private Student Loan : Generally Yes Govt. Student Loan: Generally No 

Access to Loan Forgiveness Program 

Private Student Loan : No Govt. Student Loan: Yes

Access to Income-Driven Repayment Plans  

Private Student Loan: Generally No Govt. Student Loan: Yes

Loan Limit

Private Student Loan: Typically up to your total cost of attendance  Govt. Student Loan:Varies by loan program