Entry tags:
Phone decided
I ended up going for a Pixel XL. It's brand new, and only $309; what's more, the version I'm getting has 128GB (!) of storage. That's four times more storage than any other phone I've owned!
I was worried for a moment that it would be a locked phone, but a quick query of the seller confirmed that it is unlocked, fully AT&T compatible, and the US edition of the phone. I'm feeling positive about this.