I've been using it a while now. One thing I'm noticing is there is a slight gap between the screen on the phone and the screen on the case. It often means I have to tap a little more than usual. But I've not had any rainbow slicks. I would obviously prefer not having either issue but I'll tap a bit if it means not having to deal with rainbow slicks.
Other than the slight loss of screen senstivity I'm still loving every other aspect of this case.
Still need to do my water test though...
I ended up returning mine b/c I couldn't get used to the gap. Other than that, it is a great case. My first one failed the water test. just be sure to test it without your phone first. It'll float, just put a mug or something on it to hold it down!
hope it passes for you.