I just updated to Lollipop and I don't like it. I liked all the previous versions of Android and I was very happy with KitKat when I got S5 but this update is all kinds of irritating. The worst part is white background on the notifications and settings and all the phone stuff (phone, contacts, messaging). It was so much better looking and easier on the eyes in black. It's the new Material Design thing that's supposed to give more freedom to designers and bring 3D looks but just looks bad and too bright. Also now screen uses up noticeably more battery. Luckily for me TouchWiz still uses transparent background for App Drawer.
Another deeply annoying thing - the app switcher (Overview) screen. The one when you can look at and close the open apps. You can still use it to close and switch between apps (although I like the old list version better then the new wheel one) but I can no longer go to the home screen by taping the background. It was so much more convenient when I could chose between any of the apps and the main screen in the same place. Why? Why would they remove that?
Samsung Apps updates for Lollipop are also not an improvement. As I mentioned before I used the Health app to track my movements and it just became much less useful. We get the attack of white background again and a lot of less, badly designed information. The screens are much more cluttered and I can no longer check how many steps I did in every 20 minute interval (the graph is smaller and without any scale and you cant move the check point). Also map tracker is pretty much usless now that it's no longer a real map. And a lot of cool statistics got lost too or switched to small pictures instead of something that you can touch, zoom and check at different points. But there whole bunch of stupid, useless awards. YAY! (I'm being sarcastic here).
I could install dark Materials but I would have to root the phone and there are some default things I want to keep so I'm contemplating going back to KitKat. Or I could try different launchers. But the fact that there are already options for darkening available shows I'm not the only one who hates this. As far as I can tell this is a very common complain.