Everything except CPU per thread performance, where they lead. Fit and Finish is tied with their more competent competitors (certainly some companies are worse). And you missed value for money. A 64GB iPhone 6 Plus $849, a 64GB One Plus One is $299. Specs are extremely similar.
I do not really think that is a good example. What store can the average consumer go to buy this product? The screen is very large for a lot of people.
They produce JUST the phone. They use other companies OS, they use other companies App store. They use other companies infrastructure. The phone was based on a very similar Oppo model and was manufactured in the Oppo factory. Minimal development cost there. Minimal overhead costs. Just hardware costs in the long run.
Apple has to design the phone. Design the OS. Design the infrastructure. And then market all that.
The new OnePlus phone is expected to costs significantly more then the current price. Which coupled with the "idea" that this is really just a front for the Oppo brand, it would make sense to me that they sold the first model at a very small margin to gain market penetration.
At the time the OnePlus One came out it performed average on nearly every single metric it could measured on. It definitely didn't trounce the iPhone in any way...outside of cost.
As far as "value for money", this is entirely opinion based. Absolute cost just isn't the sole factor for many people. This preference exists in all consumer markets. And, you have to consider that I can sell an iPhone 2-3 years down the road for about 40-50% of what I paid for it (unlocked version).
Also do not forget that Apple is an American company. As much as you would like to point at Foxconn and give a look of disapproval, Apple absolutely does employee a TON of people right here in America. It's not even just the direct Apple employees. Apple purchases components from companies right here in America. And those employees make good money.
Does OnePlus do this?
Do not just look at the lowest common denominator and think "If they can do, why can't everyone else?"