I'm not an expert with liquid eyeliners so I'd rather just keep using khol liners, because they've been getting more and more hybrid and there isn't a clear line between the two anymore.
This khol liner is very pigmented and has a soft creamy texture. It applies like a dream and is long lasting (Maybelline's claim is 16 hours, but I don't usually keep my make-up on my face that long, so I can't confirm this, but it does last around 9-10 hours, at least!). It blends very easily and doesn't crease or smudge on my eyelids.
The only minus I can think of is that especially when I'm tight-lining my lashes a lot of the product gets stuck in the roots of my lashes, because the tip is so soft and creamy.
Make sure you check it out, because it's one of the best liners I've ever tried. Available in black here.