I started using liquid eyeliners already at high school, as that was the fashion back then and all I remember is how difficult it was to apply them. Nothing has changed to this day in this regard, at least not for me :-). My hand is still shaky and so is the result.
Currently, I have two cheapo liquid eyeliners: 2B cosmetics 01 black, waterproof (Di) and Dermacol, glamour eyes, glittery black (DM Slovakia).
The one by 2B has strong pigmentation but an uncomfortably long handle, which makes perfect application almost impossible...plus the staying power is low, so I would not recommend buying this.
Dermacol one has a good short, workable handle and the glitter is a nice perk :-) It is nevertheless quite difficult to work with, it dries quickly so you have only a limited time to get it right. But then, I am spoilt by gel eyeliners :-). What is your experience with liquid eyeliners?