I bought this for my FNX-40. I have a Blackhawk Serpa for my XD-9 and wanted something similar but Blackhawk doens't make one for the FNs. So I found this and thought it sounded good, plus it isn't too expensive.
When I first took the holster out of the box I thought it was the worst holster ever. I was ready to just throw it away. But I had a event coming up and I needed a holster. So I decided to give it a try.
First off, the design is meant to tightly hold the gun. But in my opinion it holds it much too tightly. Drawing from the holster requires turning the butt of the gun towards you and forcefully pull up. Their thinking is to make the gun impossibly for someone else to draw your weapon. In that it succeeds all to well. But it also makes it difficult to properly and safely draw/holster.
On to holstering. In my opinion holstering a gun should require very little force, as if you conceal carry (or duty carry/open carry) you could have a round in the chamber and if holstering requires a lot of force it is possible to have a accidental trigger pull. This holster requires a lot of force to properly holster. I personally didn't feel very safe using this holster.
Lastly the force required to draw the gun means that you HAVE to have a sturdy belt. My Blackhawk Serpa holster could be worn with just jeans in a pink, not so with this holster as it would be impossible to draw the weapon.
For anyone wondering, I did use the tension spring to completely loosen it. And ...