When OnePlus started, they were considerably cheaper than flagship phones from others. At $299, the OnePlus One was a ton less than the $650 you'd pay for an iPhone 6 or Galaxy S5. You were getting a 95% flagship phone at half the price. You could get a OnePlus One with the latest Qualcomm Snapdragon or you could get a Samsung with 30% the performance and a 640x480 low-res display for the same price.

I feel like the "something new" was price. Over time, that price kept creeping up. Yes, it went from being a 95% flagship to being a 100% flagship, but it also went from being half price to full price.

It was also cool that it used Cyanogenmod which meant you got a community OS that actually got updates, but over time other manufacturers started offering updates for their phones (rather than abandoning them soon after manufacturing). And that was something new other than price. But I think the big thing was that it was a half-price phone when it launched. In 2014, it was just such an amazing deal. Today, it's the same price as Samsung phones.