I find it very comfortable and it will never slip off easily unless it has been worn too many times.
It has a lifespan as well. You can only use it for a certain number of times before the glue becomes less and less sticky, which MIGHT make it fall off a little. I've never experience it to fall off completely.

In my opinion, I prefer those fabric light ones compared to silicon ones. I find silicon ones heavier and easier to peel off by it's own. I don't have very big boobs and nubra does do wonders. Sometimes I wear it like in the video, nubra + a not too padded bra to create more cleavage.

There are different types of nubra now, those with pattern ones, bling ones, laced ones. And lots of ppl are selling it online. If you wanna know about the quality, try checking the buyer's testimonial. The one I got last time cost about RM35 and it was very good for me.