Thinking of a switch but needed some insight to make an educated decision. Thank you
G6 will be much easier to hold and use because of the flat glass screen and shape, the S8+ is actually very long in shape so pulling down notification bar can be annoying. Also, if you like cases and screen protectors, you can forget about using a screen protector on the S8+ as the curves are too difficult to even bother with. S8+ however will have a much more advanced camera, with an excellent front facing 8MP camera with focus and rear dual pixel camera that can focus instantly and look great in low light. The G6 has a unique wide angle camera at 13MP, no other smartphone in the market has that. I myself use the wide angle very often however have issues with focus speed in low light, that's where the S8+ wins. S8+ has a SD 835 and 3500 mAh battery, which means the battery is extremely efficient and you'll get very good battery performance, whereas the G6 has a smaller battery of 3300 mAh and a less efficient SD 821. And last but not least, the S8+ has a beautiful Super AMOLED display whereas the LG G6 has an IPS display. If you're concerned with burn in, the G6 is the better option, if not the S8+ is a clear winner with literally the best screen on a smartphone.
If you already own a G6, I'd say keep it. The S8+ is pretty expensive at $850 +tax and not really worth it IMO. If you absolutely need a lowlight and fast focus speed camera, opt for the older S7 or S7 Edge which is much cheaper in price.