It depends on your email activity. Push can be more efficient if you do not receive that many emails. The problem with push is not just the persistent connection to the push server, but the fact that the phone will attempt to download emails as they come in. A fetch rotation gives the phone the opportunity to combine the activity into a single session. If you receive lots of emails, both push and fetch can be huge waste of energy. You’d just have to estimate your email activity or test the energy usage. If you only receive a few emails a day, push is definitely an option.