Finally, I got my hands on the YSL Shocking Eyeliner! I was devastated as my the city YSL counter had sold out and I couldn't find any site that would ship it to Australia but I happened to come across one at Castle Hill Myer. Actually, there was a bunch of them probably due to the lack of staff working at that store. I was ecstatic and was almost tempted to buy two.
I also included swatches above comparing it to my another felt liner which is by far the blackest one I own (Illamasqua Precision Ink). The top one is the YSL and the one below is the Illamasqua eyeliner.
Whilst I feel the YSL liner is not as intensely black as the Illasmasqua one I DO LOVE the fact that it dries matte and doesn't flake. The matte finish makes it different and definitely gives a more softer but somehow bolder look. It still is very black but not the blackest black I've come across. I am so happy with this purchase. I swatched it on my hand several weeks back and was impressed that it did smudge but was removed easily as it was to apply. I'd definitely recommend this to anyone who's looking for an easy to apply matte black liquid liner that has staying power.