I have the OnePlus One still, actually. It's been in water and dropped on the ground, and somehow is still going strong. For $300, this is the best phone I have ever had, even ignoring the 64GB storage and out of the box rootability.

I've looked at the OnePlus 3, and it seems like a worthy successor. LinusTechTips on YouTube did a review on it. I'd recommend checking it out.