I've been using this for about a week now. It's a very cool design, all the Dual Shock 4 buttons and sticks are on the gun, so no worries there, unlike with the Move controllers. Makes navigating the PS4 menus almost like using a Dual Shock 4, it's just a shame that not every gun game has Aim controller support.
So far, I've been using it in Farpoint, and it's been working flawlessly. You forget you're even holding a controller, you're just in the game, holding a space rifle!
Highly recommended if you have Aim supported games.