What is the best phone to buy?

That would really depend on what you like in a phone - If  you like being able to carry extra batteries so you never run out, then an Android phone would be best for you, and likely the new LG G4.  If you really enjoy music, then the HTC One M9 might be best because it has front facing dual stereo speakers and Dolby sound, plus aptx for bluetooth.  If you like very large phones (I do too) then the Samsung Note series or Iphone 6+ might be for you. 

The Samsung Note 4 also has a removable battery.  If you like a lot of storage space, then pick an Android with a SD slot, Iphones can have large storage but they are a lot more expensive when you get the bigger space on them.  Think about what is most imprtant to you then go to a place like Best Buy where you can look at all of them and see how they feel in your hand.

Well it's smartphones  so probably iPhones

right now sony z5 premium , and one plus 2 is the best

An Android phone is a smartphone that runs on software developed by
Google and is one of the top competitors on the market for smartphones. Android phones are my FAVORITE type of smartphone on the market today.
Very clean and open source allowing you to customize and tinker to your
heart’s content. I love my Android phone and I think you would like
Android too.

If you are an android user go for android or vice versa