Thinking of stepping up from the 5in screen on my Nexus 5X to the 5.5in range. I'm not sure I want to pay the 600-plus that new phones cost, so I'm thinking of the used market. So, what should I consider? The Nexus 6P is a natural choice, but it's almost 2 years old. The Pixel XL is still a bit too expensive. Maybe the OnePlus 3T? Any others I should look at?