Hit or miss, depends a lot on personal preference...
Fireball Mountain produces some really innovative products, and the Power Angle is no exception.
Basically as you can see in the pic it adds an angle (duh) to your exsisting drop forward which allows you to mount your air system across your bicep and front of your shoulder, instead of jamming it in your ribs or pec. The beneift is you can tuck the marker more into your body and use your whole upper torso more effectively in shooting... you kinda just roll out with your torso and make minor adjustments with your arms to correct your shooting. Also, it allows you to drop the marker down a few inches so that you can properly sight down the marker and give your hopper some more breathing room when playing in tight bunkers. I have yet to find an ackward shooting position in which the Power Angle isn't effective or impairs my ability to shoot.
Some people can't stand drop forwards, others like them... if you like drop forwards and use 'em you owe it to yourself to pick one up. Search for it on eBay, they go for pretty cheap and IMHO make an effective, intelligent upgrade. I'm giving it a 10 simply because it does it's job and nothing out there can compete with it.