Do you need an upgrade? If not, stay with what you like.
If you do, in what areas? Different phones are better for different things. Taking pictures? Videos? Gaming? You decide that first. (My decision is always 1. Does Otterbox make a case for it, 2. Is there a version of TWRP for it and 3. How's the company customer service. Those are important to me. A 40MP camera doesn't matter to me - I'm not making any enlargements, and a 12MP picture looks about the same on the phone's screen. But I want backup, rooting and a very protective case. Your needs are probably different.)