I've tried out the silver shatter polish and it applies really thickly, leaving only a subtle bit of shatter effect. I did expect the polish to 'crackle' further than it did, but this may just be the nature of the silver formula which is thicker than the black ones I've tried. Because of this the base shade isn't that important as you can't actually see that much of it; you could even wear over plain nails and get the same striking effect. The polish dries quickly and stays around for a few days, but the tips do start to wear off so you need a topcoat for longevity. Overall though, for something fun and different, why pay more than £2.99 when it does the job well?
Another product they've launched into their 'special effects' range is a matte topcoat, also priced at £2.99. As expected, you need a quick swipe of polish to turn any glossy colour into a sophisticated matte effect. This is actually quite impressive as compared to the other matte topcoats I have from much more expensive brands, this stays put and doesn't rub off easily. My nails stayed matte for the life of the polish. Top marks!