I have two of these and find them to be unique and of really high quality. For this review, I am referencing Demolition and Turbulent.
Firstly, I think that these are being marketed incorrectly. They are labeled as top coats but they are not. Each of these dry to a bumpy glitter layer that needs a proper top coat to last. But that is the only downside I've found.
These are both unique combos of different shapes of glitter in a CLEAR polish. That is so hard to find! Turbulent might have a slight blue tint to the polish but it is very slight. I love this because often you find a polish that looks like it would be a wonderful top effect over whatever polish, but when you put it on, it has pigment to it and changes the look. This is where I think these Sephora X Effects polishes stand out- they are truly just EFFECTS. Fun clear effects to add a new dimension to your base polish. Which is exactly what I hoped they would be and what I wanted!
You have to top these with something like Seche Vite- they are not a top coat. They dry grainy and sandy. Don't buy them for a top coat- but DO buy them as an effect! And for that, they are fabulous!