I think of it like this:
Someone goes and and buys a high end sports car, such as a McLaren. This person has wanted it for a long time, it fits the needs of this person.
Then, someone else comes along and buys a Corvette. They have wanted this all along as well.
The Corvette owner then starts to ask why the Mclaren owner spent twice as much on a car that performs just as well. The Corvette owner start telling him things such as, "This car has just as much horsepower and torque and it cost me much less", and "This car does everything yours can do and more".
Then they decide to race them. Both cars, while having different engines and everything, perform about the same. Even though the Corvette has more horsepower and better specs on paper, the McLaren and it still perform relatively the same.
The same can be said of the OnePlus One and the iPhone 5s. The 5s, while costing double the price of the OnePlus One, fits the needs of certain people better. Yes, even though on paper the One smokes the 5s in terms of hardware, both phones perform about the same. It all comes down to personal preference: Personally the iPhone does exactly what I want, and is perfect for me. That's whyI pay $700 for a phone compared to $350