Let me start off by saying that, at 10$ a month for a subscription, this eyeliner more than paid for my subscription as the regular price is 14$. ;)
This eyeliner is a hybrid between a pencil eyeliner and a liquid liner. The product that is being delivered is liquid. However, I've worked with felt tip liquid liners before and this Be a Bombshell eyeliner is far superior. The advantage is, as the picture showcases, the pen-like shape that is pointy to wider. So it gives you far more flexibility in how you are applying the liner than either a conventional brush that accompanies a liquid liner or the felt tip liquid liner. You merely need to angle the pen a little bit and will give you a wider line. If you keep it straight, it's going to give you a very thin line. Essentially, I found that it was extremely easy to use the pen.
The black line that it yields is also very intense, which I really liked. It is very much akin to what a liquid liner would give you and, indeed, it is a little liquidy. Contrary to liquid liners, though, it's not nearly as liquid so it dries quickly and you have less risks of unwanted smudges. That being said, given that it dries uber quickly, it doesn't smudge well at all, which means that you'll likely need to use something different if you want a smudged line.
Note that, given its liquid nature, I wouldn't use it at the lower lid waterline (you never want to put a liquid liner there... burns like hell... yes, I know that from experience). I did apply it at the lower lash line with great success, actually and it made a very nice line.
The price is 14$, which is on par for non-pharmacy eyeliners (they range around 15-20$) but is obviously more than pharmacy things and e.l.f. products.
I gotta admit that I'm madly in love with this eyeliner and will likely purchase it again once I run out. I also would highly recommend it to anyone who wants to have a liquid liner application but isn't used to doing it. This is so much easier to apply!
In this pic, I'm wearing the Be a Bombshell eyeliner.