[LG G6 Questions and Answers] SolarisSixth:
Well, this is ironic.

I have a G6 and my friend just got an OP5 so we compared a few things. I have a pretty good idea what the differences are.

Design: Of course this is subjective, depends what you prefer. The OP5 is thinner, but I like the G6 better. That's of course your preference, but once you go bezeless, it's hard to go back.

Battery: I'm actually getting great battery life on the G6, however, the OP5 is just better. The battery size is the same, but the 835 is more power efficient, the screen is 1080p instead of 2k, and Android 7.1 has more battery optimizations than 7.0. As well as less bloat running in the background.

Of course again, that depends on your usage. Speaking of display:

Screen: Both are gorgeous screens, 5.7 2k vs 5.5 1080p (and yes, the G6 is slightly smaller even with the bigger screen). Both are nice, and it's really your choice. The G6 screen is gorgeous, and LCD which is really one of the best. The OP5 screen is a nice dark amoled and has great colour. You won't be disappointed by either screen, it all depends on whether you really want the nicer denser screen, or of 1080p is nice enough, taking I told account battery savings.

Speed: Day to day usage, both phones are great. I really see no stutter or lags on either device, except for the occasional hiccup in an app. But that's the app more than the hardware.

That being said, the little things is where the OP5 flies. Unlocking it is nearly instant. The camera loads ridiculously quickly. And of course games load quicker. If the G6 could be rooted and some bloat deleted, it could probably do a bit better, but stock out of the box, the OP5 flies... unlike the G6.

Camera: I'm not a big photos guy, so I can only give you some simple experience with that. Both rear cameras are very similar quality wise. The OP5 gets the bokkeh effect, and the G6 has the wide lens. Again, kind of comes down to your preference. The front facing camera is better on the OP5. That's no competition. I assume LG could not fit a better camera on the small bezel. That being said, it's not a TERRIBLE camera. As long as you have some good light, you're fine. It's just low light that ruins things (like most cameras anyway)

Regardless, both phones are pretty awesome. They both do very well for day-to-day. They both look very nice as well. Although I'd give the "looks" advantage to the G6, especially since the OP5 looks just like the iphone7, which personally, I really don't like. But it doesn't mean its a bad look or anything, again, very subjective. The power though, goes to the OP5. Again, the G6 isn't bad by any means, but you can really tell which phone is more powerful when putting them side by side.

I tend to edge over to the G6. I feel it's a more no compromises approach. Despite being overall less powerful, it doesn't suffer in day to day, and looks great. The OP5 is definitely more of an enthusiast device, but I would pass on the looks.

So unless there is a specific reason to get one: like rooting, the front camera, the display tech (LCD vs amoled), the processor, etc. You'll be fine with either device.

Take a look at the pricing around you. I got the G6 from a carrier so I paid less up front, but overall the OP5 is a bit cheaper (at least here) so that's a consideration.

Good luck!