Well, I have mixed feelings.
First off I'm a small boob chick (B-cup) and while it did cover the girls and the nips.... It didn't really provide any support or make a difference. I think its great for very thin or exposed garments that make wearing a regular bra unsightly or inappropriate. Even with the strings, I struggled to make any semblance of cleavage. Based on my experience, I think these guys are better suited for those with a fuller chest.
As far as the material and its ability to stick: I'll give it to them that it's definitely soft and comfortable to wear with little irritation. The silicone sticky gel is Strong & Sticky (check the video). I have sensitive skin and the bra was comfortable and easy to wear for a few hours (probably longer, if you don't sweat much.
The bra is quite inexpensive and arrived within 5 business days and was shipped very,very economically. Not in a box but in one of those small white postal/parcel packages with some bubble wrap on the sides.
IMO, its probably worth it simply to avoid bra lines and to cover your nips. If you are looking for help in the cleavage or support department, this are NOT the bra for you.
Below is a Video of the actual bra and the site.
Interested in purchasing or checking it out: Click here