Haven't had it under the full nightime lights yet. My pool light install was a pain as the conduit broke and they had to dig it up last week to replace. The electrician hasn't come back to hook it up yet. On a cloudy day, it looks more grayish/blue. Again, to me it's more natural looking than a deep blue that is very artifical.
I know that the liner I got was a 28mil liner which I think is the thicker/heavier one over a stanrard one. the 28 might just be the walls....I can't remember but I know it was a better choice over other brands my PB uses. He really likes this company. They also make the CoverLogic safety covers which I will most likely do once my deck gets poured..