It's not quite as forgiving as a pencil liner - You can't just smudge it into a smokey eye if you mess up. But it is so much easier to apply than a liquid liner (it's got a thicker consistency) and creates a similar look.
It is very easy to apply, but if you are using the brush that it comes with than it may become difficult and you may get frustrated. Try getting a good quality brush to apply it and then it will be easy.
It's really easy to apply! You can use the brush it comes with works nice but I think it is a little too thick to use unless thats the look your looking for. But you can use a different brush of your choice or a pencil and just dip it in there and use that to apply it if you like using that technique better.