I tried it.
Positive: Very, very fast bootup. Twice as fast. Pretty amazing.
Negative: Dark, dark, dark! Using auto-brightness, the base setting is not viewable for me.
Conclusion: I would have to say it's not for me, because I like flashy, which this is not. It's basic. However, I know that flashy takes memory and this is designed to fun fast and fleet, which it does quite well. I do like the speed and commend the Dev for designing this as fast as it is.
Finally, the deal breaker for me is the minimum brightness. I have to be able to see my phone and I can't at the automatic setting. If this was configurable, or more aptly put, if I knew how to do it, I'd play with this a bit, but I don't so I'm changing it out and trying something else.
So far, I like black glass x better.
Steven