I was considering it because the smaller iPhone is a better size practically unless you have huge hands, but the 326ppi put me off, I can notice jaggies at around 10 inches, 6+ is 401 and noticeably sharper. 6s really should have 1080p / 450ppi display, but apple are leaving that till 7.
I was thinking about it 326ppi came out on the iPhone 4, thats 5 years ago now and no pixel density increase. At the release retina was a revelation and wonderful improvement, but 5 years later and no increase in sharpness, apple has been a bit lazy on this - at lease the 6+ has over 400ppi, it really makes a different to my eyes