I have used the Gecko II for just about an entire season and I can tell you that it’s incredibly versatile, and I use it almost exclusively now for a support and rear bag.
Where it comes into it’s own is shooting from the bottom legs of tank traps, off of angled bars and from all parts of metal and plastic barrels (of course off of barricades, too). At a recent match it got some interest from shooters after I used it on a tank trap stage (only able to use the bottom of the tank trap legs). That was the only bag that didn’t need to be held in place.
The sticky nature of this bag allows me to free up the hand I would otherwise be using to hold the bag in place. It’s holding up well even after consistently using it on rough wood surfaces. I’m not trading this in for another barricade bag anytime soon!