hi
c2c means corp to corp recruiting.In this case payments to be done by 1099 form.after recieving payment you are the responsible to pay all the taxes subjected on your earnings.
w2 is working with 1040 form.in this case you will be paid after deducting all the taxes which are supposed to be paid by you.your employer will deduct all the taxes and he pays on behalf of you,and he keeps you under his payroll.while you are on w2 you are eligible to get unemployment fund also,and with 1099 its not.