I find the note 3 camera to be good in good lighting. In low light it's rubbish. However outside I prefer it to the iPhone 5S because of the level of detail you get in your shots. You simply don't get that with the iPhone 5S. Yes it's not As easy to use, however take a few shots and you get great pics. It's never let me down for important occasions and I've been pleased with my pictures.
The OIS on the note 4 should help to improve low light performance and combined with the excellent camera on the S5 it should be a very good camera.
Yeah, if the lighting is perfect, or I'm outside the N3's pictures blow away the 5s. Where the N3 falls short is as you say low light, but I am extremely disappointed in macro/close ups, it's very hard if not impossible to focus. In all fairness I haven't delved into the settings, I'm kind of a lazy picture taker just get er done kind of guy.
I have no idea if it will, but I hope OIS helps with macro shots also.