Reviva Labs Hypoallergenic Black mascara that I bought at Whole Food's Whole Body store for $9.
On the right (my left eye), I applied Loreal Paris Double Extend Lash Boosting Blackest Black mascara that I found on clearance at Rite Aid for $4.
Honestly, the natural stuff is pretty pathetic. It feels way too light on my lashes (like water, almost) and makes them look "spidery" in the words of my mom. Trying to put on more than 1.5 coats is pointless and doesn't help at all because additional coats don't add anything. There's no substance to it.
The conventional mascara is great as always. I usually change brands every time I buy mascara, so this is just another one I'm trying. This particular brand has a white first coat that's supposed to strengthen lashes and then the top black coat. I can layer it and layer it until my lashes look like I want them to.
Both brands had a straight, non-special brush, so that's not a factor in their performance. I was really rooting for the natural mascara to work, but this particular one isn't going to suit my preferences. If you prefer the almost-not-there mascara look, you may love the Riviva brand, especially since you can feel good using it. I've grown accustomed to the thick-lashes look, though, so I think I'll keep using the conventional type while I continue to search for a natural mascara that has the impact I'm looking for. :)