I find it easier to aim with this, feels good IMO.
Makes your setup longer. Not adjustable, might feel odd to some.
After not being able to aim with my Phantom really well, I borrowed a friend's OC Phantom, and he had a L-stock with the M-16 grip on it, running his 22ci/3,000psi HPA tank California style (tank mounted on the stock for those who don't know what that meant). I found it much easier to steady my shot using this, thus making it easier to hit people. There is a downfall of course, and that is it makes your setup longer. It's also non-adjustable so those of you with a different taste, you're out of luck. It is a lot cheaper than the adjustable T-stock though, but if you like the M-16 grip on your Phantom, this is your only choice. I thought it felt fine though, I recommend it as a cheap alternative.
Get it if you can't really steady your shots, I found it to help me out a lot.