So here are my initial thoughts that some might be waiting to here:
Overall, the OnePlus 3 is very impressive. Doze + stock android are a force to be reckoned with. The screen "issues" people complain about seem to be very overblown. For a 1080p Amoled display, I am quite pleased with it. I do enjoy an ambient display as well, especially the hand waving gesture.
Let's move onto the gestures. I think these features are nifty and usable, yet completely optional. I haven't encountered a mainstream phone with music gestures. You don't even need to turn on the lock screen for music. The V is a nice in a pinch flashlight shortcut. The circle with the camera is nice, but it might not be as appropriate for me. The customization this phone offers is pretty impressive.
Customization is often thrown around like crazy on Android devices. At their very core, Android devices can have widgets, live wallpapers, launchers, developer features, etc. You make your phone your own without any issues. However, the OnePlus 3 brings its own variation to the table. There is no theme store, but don't fret. You can change the icons from default to a couple of choices called Rifon (squares) and Dives (circular). In addition, I have yet to use a phone that can transform between capacitive and virtual buttons to the degree the OnePlus offers. I can switch the capacitive buttons between the app switcher, back button on either side. Used to a Galaxy? Put them in reverse order. You can even change what the long presses, double taps, and other button features do. I have a double tap to launch camera (ala Galaxy S6 or newer Galaxies) and long press for the Search Assistant (Google Now on Tap). The display has various customizations as well. I enjoy the dark settings theme as well.
Dash Charge is as great as advertised. The phone charges incredibly fast so far. I saw a 6% jump in a couple of minutes and I was take by surprise. With OnePlus' standard, you can rest easy about not abusing the battery through quick charge as much since there isn't much heat being produced like other flagship smart phones. It is a refreshing change of pace from the iPhone 6S Plus' charing time, which is abysmal by today's market standards. I cannot fathom why Apple decided to stick with the Lightning standard for so many years. From the iPhone 5 to possibly the iPhone 7/6SE/Whatever it's Called, the same standard with little improvement. That screams disappointment.
Processor and RAM performance are top notch. I can use apps from 2 hrs ago without refreshing. 6GB isn't necessary, but it's a nice advantage that allows you to use apps without having to worry about refreshes or closing them out every so often. I'll run benchmarks later. I have not noticed lag or anything at all. The 820 is known to be the best, so it's in good hands with a near stock android experience. I have more time to explore.
Camera performance: I normally don't play around with cameras. I decided to mess around with the settings. What was a bit surprising that I cannot turn on automatic flash with HDR automatic and have "HQ" on. I assume HQ means "high quality." Maybe others can point that out to me if my camera app is not reacting to commands properly. I have heard it's a solid performer that just gets the job done well and doesn't aim for bells and whistles like the S7 or iPhone. Okay, those guys have better software features, but it's hard to complain at $399. I will leave this as incomplete as I try the camera over the upcoming days.
Call quality: I spoke to one my friends at his college campus when he was in a dead-zone while he used his OP3. The phone conversation went well for the most part, just a few audio cut outs, but I blame the deadzone for that. When I spoke to a family member with my Beats on while was just listening to music, the other person couldn't hear me until I took my Beats off. Maybe that might be an audio bug? I don't see that as a huge issue right now.
Data speeds: Wifi speeds are fine with the OP3. The data speeds on my phone are about what I expect because I have bad service in my area. The ping is low, about 50-56 on three tests. Avg of 18.04 MBPS down, 2.18 MBPS up. That's on 2 bars of LTE with a drop to HSPA+. Time will tell how this guy performs outside my area. Curious to see that.
Software: I love the clean polished software experience. I normally think stock is bland, but that's not a bad thing. The gestures and customization improves it quite a bit. Stock is good for phone performance though. I look forward to the upcoming additions OnePlus has in store for us OP3 owners. I enjoy the Google Dialer for sure since it is simple yet versatile. Visual voicemail is a huge plus for me since I enjoyed that on iOS. Predictive dialing is such a refreshing addition coming from a mainly iOS experience for the last few months. More to experience on it.
Battery life: Too early to tell, but 3000 mAh on a 1080p Amoled screen has me expecting better performance than the iPhone 6S Plus. In addition, Dash Charge can make up for any battery issues if Screen On Time isn't up to snuff. I have seen some various reviews pointing to alright to decent battery life. My friend had no complaints when he recommended me this phone since he just got his last week.
Hardware: This phone is a beauty. I love the fingerprint scanner/capacitive home button design. The front facing white looks very classy. The soft gold back says "I am trendy, but not flamboyant." The antennas are reminiscent of the HTC One line, which isn't too bad. I don't mind them at all. The camera hump is a bit much, but as MKBHD says, more battery would make the camera seem more flush. Maybe Apple can listen to that suggestion since the S6 to S7 change took that into accord (2550 mAh battery to 3000 mAh respectively).The chamfered edges are nice as well. The alert slider is inverted, so that's perplexing. I wish the OP logo was a bit smaller since it feels like a distraction to the eye a bit.
I would rate this phone an A- or 9.3/10. I give it that so far minus the camera experience. What could've been added was the bigger battery to make the phone more flush without having too much of a size increase. Companies love to go for this slimmer is better model, which takes away from battery capacity and forces processors to be more efficient. Wi-Fi Calling missing was a huge bummer. I could use that, but I will still give this phone a chance to be my daily driver without it. The fingerprint scanner on this baby is top notch and I love how you don't have to turn on the screen to get the phone to read your biometric to bypass the lock screen. There could've been dual bottom firing speakers here or front facing speakers because the bezels above and the bottom of the screen provide some room, which would need to alter the home button and maybe toss out the capacitive button scheme as it is, which forces it to be much smaller or even on screen buttons could've done the job. OnePlus has a winner in the OP3. They finally got it together and put an all rounded contender. It is the best bargain phone you can get below $400.
TL-DR, I like the phone and think's very solid. You have to be nit picky to get into flaws. I haven't tested out the camera yet. Battery life will be telling after a week or so. I recommend it so far on a few hrs of use. Fingers crossed it can be my daily driver.