How's the display on that? I'm on a Note 3, and I really like the fact that I've always been able to see Samsung's AMOLED display in the sunlight. I also have bad eyes, so I tend to keep the display pretty bright in the dark. It's always seemed so much more vivid than other phones I've compared it to, but that's been a while.
EDIT: And where the heck do you get one in the US?
Oneplus 3T (exact same panel as in 5) has good legibility in sunlight, I had no issues with it. As for vivid, you can configure display calibration on Oneplus to suit your taste. Unfortunately there are no gamma sliders for fine grained control, only 3 or 4 predefined settings.
EDIT: And where the heck do you get one in the US?