I need another black liner about as much as I need um, nothing. The Insider Eyeliner in Onyx ($14) does have a nice thin tip which makes it easy to tightline lashes or use on your waterline. The formula includes antioxidants and vitamins to protect the delicate eye area, which is a nice touch. I did experience some skipping on one eye, which I didn't notice until taking pictures. I also experienced some pooling/smudging in the corner of my outer eye, probably from the waterline. The upper lash line wore well throughout the day. I don't usually line my waterline as I've got small eyes to begin with, and honestly, when I see myself in the mirror I think "replicant". So, out of the five products, this is my least favorite and will probably not get much use.
I'm neutral about the Buxom Lash Mascara in Blackest Black ($19). The brush is a bit on the large side for my taste, and I find it hard to reach the inner corners of my eye with it. I didn't have any issues with clumping or smudging however, so it seems to perform well. It just didn't wow me, but maybe I'll grow to love it. That has happened before.
Disclaimer: I purchased these.