Which way should I get iPhone battery replaced?

I can send it into Apple by mail or I can make an appointment with Apple store. Needs opinions or suggestions of the better choice.

Apple Store will be quicker.

Take into the Apple store and you are out with a new battery in under an hour. How close are you to an Apple store?

Batteries plus can often do it in under an hour for less money than apple. Depends on the phone.

Take it to the local store.

If you can easily get to an Apple store, go there. Otherwise you have to send it to them.