If you have your company cut you a check (even if you will move the $$ elsewhere), you will get hit with a penalty fee. You never see the penalty - it gets taken off the top.
You can recover the fee by placing the funds + the penaltyinto another account and the file for the penalty reembursement on your taxes.
If you take the $$ and do not roll it over, yoiu are also liable for the full amount being considered taxable income.
So in theory, a person with a decent salary could lose 40-50% of the 401K after penalty, Federal and State taxes.