I bought this in a purple colour over 2 years ago from Glassons for like $5 or $6 (still going strong, not dried out). The colour is just beautiful, very metallic and pretty :) It does need more than one coat so that's it's not as sheer, but for the price, I was expecting that. It lasts for a while on the nails, especially with a good top coat.
Honestly, the most impressive thing to me is how long it's lasted without going yucky and drying up - even more expensive branded nail polishes haven't lasted as long.
Bys had been a great gateway polish for me to try different coloured polishes that I wouldn't have normally bought at a higher price point. I have owned a variety of colours but my favourite has been the silver which I wear as a base coat under silver glitter polishes so I don't have to wear so many layered of glitter (which is a pain to get off!) Having said that I do find the packaging quite cheap and the lid is not the perfect shape for my fingers. The wearability is also lacking compared to others.
Tips: See above re silver and glitter polishes, best tip ever!