Do you fancy yourself a smartphone expert? Maybe you ought to help OnePlus evaluate its phones by applying for The Lab. It's a community review program for the OnePlus 3, which is going to be announced in a few weeks. OP is calling this a "peer review," but it's not like they have time to change anything if the fans don't like it. OnePlus just wants to create its own review of the phone with users writing it.
The Lab is only accepting sign-ups for the next few days, and there's no guarantee you'll get in. OnePlus says it will review applications and choose 30 people from around the world to be part of the program. They will use the phone and submit a "review" to OnePlus. There's a 500-word essay section of the application where you must explain why you should be chosen, so you have to put forth at least some effort. Whatever comes of the review will be published in some form, at least this is the implication.
So, why do this? Knowing OnePlus, I'm tempted to say this is about 90% PR. After all, the phone is probably going to come out in a few weeks and it's passed regulatory certification in a few countries already. For all intents and purposes, the OnePlus 3 is done. The feedback OP gets from users won't change the device. Maybe there could be some software tweaks, but I think OP is mainly looking to have its collective ego stroked here. It's pretty likely this "community review" will paint the OP3 in the best possible light.