SQUEEE!!! Honestly, I've wanted some of this stuff since I first heard about it, 9 or 10 years ago. My friends friend in America had some, showed us via a shitty webcam and I _Wanted_ it.
Soooo, 10 years later, on a casual Sunday, post-work mooch around Wilkos, mom spots some and says "Ooooh, that's weird", to which I replied "OMGOMGOMGOMGOMGOMGWANTEDTHISFORYEARS". And so, it was purchased. I have painted my nails with my usual pastel colours of yellow and green (though it looks blue), and then put a top coat of the crackly crackly on. HAPPY.
Really really happy! I'm not great at applying nail varnish, at all, but this stuff is really good. The brush is quite fat and wide and allows for a whole-nail application -- on thumb nails (mine are huge) this is pretty useful because repeated strokes disturb the previous layer and affect the crackling. Also, I need to learn to let my base layers set properly properly, as opposed to 'meh, it'll do' which is my standard. I'm currently missing a chunk of nail varnish thanks to my belt buckle. It takes a bit of getting used to, when you apply it, it looks as though it hasn't quite applied properly or evenly. If you apply more coats you'll get thicker areas of black; if you only apply one quick layer you get narrower stripes.
Quite excited about taking this stuff off and using a red base layer...