S120 is an excellent camera
May I ask your opinion of the G15s IQ.
PMFJI, but I prefer the G15 IQ to that of the S120. I've had two S120s and both showed some color fringing at edges when shooting f/1.8 to f/2.8 wide open (24 mm). The first was far worse than the second -- and my S100 did better than both under the same conditions. Note: A minor niggle; the S120 excels at fast AF, even in low light where my S100 will not focus at all -- plus I prefer the mp4 movies of the S120 to MOV of S100 and G15.
A big plus of the S120 is that it goes wider than the G15/16: 24-120 mm vs. 28-140 mm. Big plus of the G15/16 is faster lens (f/1.8-2.8 with zoom vs. f/1.8-5.7) -- and the OVF which I find usable on my G15.
And of course there is the size difference.
As an aside. I bought the S120 because I feared my S100 (Lens Failure S/N range) would fail and leave me without my small camera. After S120 #1 arrived my S100 did fail. Five days later it returned from Canon Service all repaired at no cost. In the end I returned S120 #2 because for shooting outdoors in good light the S100 IQ just seemed better to me -- and now I trust the S100.
But not having an S100 the S120 would have been a requirement vs. using my iPhone 5S for such shooting.