In addition to Gmail and App,there are other options.
1.SIM card is a good way to transfer contacts actually. Since the SIM card is removable, you can save the contacts in the card and then plug it into the phone you plan to use to easily transfer contacts from Android to Android.
2.When you export contacts to SIM card, have you noticed that there is an option Share namecard via in the Export contacts window? This is an available way to sync the contacts actually. This inbuilt feature allows you to migrate the contacts from Android to Android via Bluetooth.
3.MobiKin Transfer for Mobile. With it, you can simply connect two phones to the computer, and transfer contacts from Android to Android with one click.