What phone to buy?

S4 is the after series , Just choose s4 but its up to you

IPhones sucks, do a comparison online with the specs, any android can beat the IPhone.
I have a dual-core Wiko for 2 years, still works great and is super fast.
Dont waste your money buying an iphone, or a Samsung (samsung's are filled with trash app's, makes them slow).

Check the Major Chinese brands, like Wiko, BQ, Xiaomi, or Huawei. ( http://www.pcadvisor.co.uk/test-centre/m...k-3616945/ )

Also check some online specs comparisons.

xiaomi for me :D ( im using it )

My S4 has been really good to me over the past few years. I think it's time to move on to the S7 if it has an SD slot.

Samsung Galaxy S6 is the best for me

I'd go for the S4 - But I am an iPhone fan myself

Buy an OnePlus One or an Flagship phone.

Oneplus 2

obviously.

Yeah the OnePlus 2 is a rly cheap and good flagship phone

You can buy an iPhone 7 Black 128GB. You will appreciate this phone.