Yes, the movement is still there. I can imagine that a back protector would alleviate this issue, but personally I'm not particularly worried, I think it will be ok.
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Yes, I have the SGP Ultra Optics. Two things I like about it - it has a very good balance of anti-glare vs clarity (clearest anti-glare I've seen), and it has fewer cut-outs around the earpiece vs the Power Support version, providing a cleaner, more minimal solution.
I'm sorry but the ultra optics have the feature of anti glare? Because the one I tried doesn't, but instead anti fingerprint, if that's what you meant