I've got my new 950xl for 3 days now and I can do a quick comparison between the 950's AMOLED screen and the 1520's IPS one:
-AMOLED has pure black BUT, the screen itself (not the glass) is far more reflective. So when there is light, the blacks have blue/green reflects, and so, are not really better than the clear black IPS. In a dark places, there are just without comparison, cause there are just deep black, where IPS is glowing grey.
- AMOLED turns blue-green on white screen whith a 20-30? angle from normal, ips glow is far less annoying. That's boring cause on some image too, the blue tint appears and I generally look my phone with a 20? angle, bottom is white and top blueish.
- AMOLED has more vibrant colours, allowing to set the brightness to 30%. (but automatic brightness doesn't seem to work on my 950xl). I enjoy it more than what I thought first.
- on the amoled there are indigo shadows following grey-like icons/images when scrolling (typically on photo app when photos are not loaded) like reverse ghosting, and white text on black background slightly turns brownish during the scroll.
- the IPS screen of my 920 "burned" to brown in 1 year. The IPS screen of my 1520 got 3 small bright spots I can only see on white screen, but still exist, they appeared after 16months of use. So I don't think lcd have better life time than AMOLED.
AMOLED are cheaper to produce, so we will see more and more of them on mobile. We just have to get used to that. Both technologies have pros and cons anyway.