Rimmel is probably my favourite makeup brand. When I switched to this liquid eyeliner I wasn't disatisfied. It goes on very smoothly and the colour is very prominent making your eyes stand out. It wears well and you don't have to reapply.
If you make a mistake you can remove it quite easily and you don't have to take it all off and start from scratch.
Despite the size of the bottle it lasts for ages... I've had it for a while now and still have plenty left (and I use it everyday)
It may not be the cheapest liquid eyeliner but it's definately worth paying the extra pound or two because this is the best!
Its quite slim and compact so won't take up alot of room in your makeup bag and it can be used in small amounts for day wear and more if you're after a rock chick/smokey eye type look for the evening. Be careful not to get it in your eye though as it does sting!