Auto loans are not one size fits all, so your choice of lender really depends on your needs, credit history, and relationship with your bank.
If you have a good relationship with your bank, you may be able to get a loan with more favorable terms. However, if you have a good credit history, it may be easier to get those same terms from the comfort of your living room by applying with online lenders.
The real important thing here is that either option is going to be better than relying on dealer financing.