no idea how much you're looking to spend, but if you can manage the equivalent of 450 US dollars then take a look at ZTE Axon 7. cost to performance wise it's one of the best android phones ever made.

not used either of those phones but between I'd take the s5.

between the 2 .id personaly go for the s5 not that lg 1 thing i cnt stand is a non removable battery.

G3 has a removable battery

But g3 is a bad phone. It lags and gets hot. The chip cant handle the 1440p screen.ive had a g3 for 2 years but got an s6 as a main phone last year because i couldnt stand the lag and sweaty palms from the heat lol. Plus the long charging time.

I forgot, if you would prefer a phone that gets more community support in the form of custom roms and kernels you need to find out the specific model with Samsung Galaxys. some will have a Samsung made chip others will have a Qualcomm chip, it's the latter that gets more development if that matters to you. if it doesn't then the Samsung chips are excellent performance wise.

I'm facing a similar... I was using a G3 mini that got lost this weekend..
don't what to choose between the G5 and s7edge.

How was camera performance? Good, bad or worst?

The laser focus works well but not as grisp photos compared to a s6. Also the g3 has no bright colors due to an ips screen but it looks even less than other ips screens. If you want nice colorful screen and pictures the samsungs amoled is superb.

I'd say try find a LG G4, I wouldn't touch either a G3 or GS5 at this point....or if you can get hold of one, get a OnePlus One.

I've used an S5 before. I liked it. The fact that it's waterproof and dust resistant is always a good thing.