Still an iPhone 5s User - Need Phone Upgrade

[bachiekins]

Hi! I'm still an iPhone 5s user (please don't kill me). I am trying to look for a new smartphone that can easily support my needs. As follows:

1. Email savvy - can be used almost as a laptop. As I am on the go and need to constantly reply. Should be able to hold multiple email accounts as well. I am handling more than one account for the company.
2. Memory - built in or expandable, no issues as long as it can hold most of my documents, photos, apps, etc.
3. Battery - i know there are available power banks, but the more long lasting the better. The very reason why I need to let go of my current phone is that the battery easily drains out and over heats.
4. Value - I ask this as there are a lot of new smartphones, new brands with almost the same features. I really need a long time companion. my current phone has been with me for more than 3 years. I don't also know if I'll go with another iPhone.