I'm going to be honest and say that the BellePierre packaging looks cheap. It looks like I got it at a dollar store. Urban Decay packaging looks and feels high end. I go through eyeliner too much to care about the packaging but I know it matters to some people. Now to the important stuff
The product is the most important thing. Urban Decay Perversion is the blackest liner i have ever owned. BellaPierre at first swipe is the same as most black liners but with a second swipe it is just as dark as Perversion. It passes the color test. Now the second most important thing is the staying power. This is what I loved the most about this liner. I have oily lids. I have to constantly check my eyes to wipe away smudges. UD Perversion stays put the longest and BP is right up there with it. I tried to wipe the swatches away to do a test and they would not budge. I had to scrub with makeup remover a few times to get them to come off completely. The day after I wore BP out to the supermarket and the bank and it wore just as well as my UD.
If the Urban Decay liner is just a bit outside your budget I definitely recommend the BellaPierre. I will probably repurchase this when I run out