There really is no advantage to having your mortgage held by a portfolio lender. The rates are usually the same the only difference is that the mortgage usually will not be sold off many times over the life of the loan.

Many times a portfolio lender will have programs or different guidelines that are not typical of loans that are sold on the secondary market which follow FNMA and FHLMC guidelines. Therefore you may be able to sometimes obtain a certain home loan program that you may not normally be able to obtain due to your certain situation, by going with a lender that offers a portfolio loan.