Here is a comparison between the G3, S5, and Note 3 screens. As you can see the AMOLED is heavily saturated when compared to the G3. The 2k screen stands out in comparison with the amount of detail that it displays. The blacks are close in color to me at least, but you can be the judge of that. All of the phones were on AUTO brightness for consistency. Pictures were taken with the S5 and the Note 3 respectively.
The G3 is a comfortable size, and I prefer its size over that of my wife's S5. I really enjoyed my Note 3, but this phone just feels much better, and the back buttons really make a difference.
(I had another picture but the file got corrupted for some reason, I'll retake it and post it here)