I bought OP3 and I'm a fan.
Zero problems with software and hardware, they held the promise for Nougat and there were no major bugs in it, even though it was obviously a bit rushed. Though i personally could not care less about Nougat. I appreciate OOS4 changes (like edge to edge notification shade) much more.
Just don't expect wonders in low light photography. I went in with not expecting good performance there, and I got exactly what I expected
But the ultra fast and smooth operation and multitasking and speed of the animations, makes up for any minor shortcoming for me.
Though, I bought it for 400€. Now it's 440€. But i suppose i'd still go for it, because that was my absolute limit pricewise.