I originally shunned this attachment in favor of the Rapid Fire System, due to two seemingly legitimate reasons: I believed that the Refractor Cannon was "the same thing" and, since I was already getting the scope, did not see the need for this one. The Refractor Cannon, one of the options available on the Scope accessory, is NOT the same weapon offered by this accessory; it does less damage, but possesses a greater range. I also believed the hype surrounding the Rapid Fire System, which turned out to be a little less than advertised. I purchased this system today, seeking to round out my collection.
I docked them one star on this review because the Refractor Launch System was clearly advertised as having the ability to inflict a one-shot kill on the enemy striker. It does not. Granted, the damage done by this accessory knocks the enemy striker's life bar down so far that one shot from the Stealth Strike weapon will finish it off, but it's still not as advertised.
The system is a bit awkward to use, requiring the user to press a soft switch on its side while firing the striker, but I can see why this limitation was enforced. Giving the accessory its own weapon option would have been too great a hindrance on the user, due to its sluggish rate of fire and reload time. It's also a very powerful weapon, which could tip the balance (unfairly) in favor of its user without requiring an additional step.
By far, this accessory's main advantages are its power and its accuracy. Despite the crippling disadvantage of being a short-range weapon, its user needs only to aim in the general direction of his target and fire. The wide angle beam it possesses will inflict immense damage on anything it hits, reliably and easily.
Though I rank its usefulness as a bit less than the Scope, I definitely recommend the Refractor Launch System over the Rapid Fire System. The tradeoffs in rate of fire and range are nullified by the Scope's options (if you're using one), and the Refractor Launch System grants its user a powerful short-range option WITHOUT the need to stop firing long enough to switch weapons. Those two points alone make this the attachment to get...right after the Scope.