I'm still a bit skeptical of OnePlus because they don't have the best customer service last I had their phone. Their Bluetooth in the past had lots of latency, don't know if they improved on that. Also one thing that bugged me severely was at least their first three phones (One, Two, and X) had this camera focus hunt issue in video recording, where it hunt for focus nonstop, I believe the 3 had something minor as well.
I don't think the OnePlus5 will be $333 in the US market. As they work on improving their popularity, which I think they did a great job to take over the Google Nexus market which Google dropped, then they will continue to slowly increase their prices, probably closer to $500 range.
However, I love the form factor of their OnePlus X, it was a slim and beautiful device, if they make an X2 I would consider it.