OP3 is worth. It's probably got one of the smoothest performance experiences on any phone apart from the pixels.
Only issue with the OP3 is customer support, if you can get it somewhere that offers its own warranty service (just an in warranty exchange) then go for it as the OP service is a bit shit sometimes.
With the OP3 you get a better camera, performance, display and one of the quickest finger print readers on the market as well.