The AER9 was actually not the top laser rifle in service at the time of the Great War. The model line went up to the state-of-the-art AER12, which saw service in a handful of specialty units. The reason that the AER9 is much more commonly found is that it was much sturdier and more reliable than the models that followed.
The AER9 features a titanium housed crystal array which proved to withstand long years of exposure to the elements much better than the gold alloy housing of the later models. As a result, the crystal arrays stayed focused within operating parameters, rather than falling completely out of focus like the newer models. Power is drawn from microfusion cells and processed through a wave/particle diverter manufactured by General Atomics International. The diverters are protected by a carbon-fiber housing, preventing frequent malfunction, but when a diverter fails the weapon becomes unusable.
As with all energy weapons, the AER9 can suffer from poor performance if not properly maintained. The crystal arrays and non-mechanical components are delicate and if not properly serviced can lead to a loss of beam intensity, overheating, and energy regulation failure.
The laser rifle has no iron sights, but compensates with excellent zoom. It can be upgraded with a scope, making it less effective in close quarters, but thanks to its good accuracy, it can be used as a medium to long-range weapon. The laser rifle makes a decent starting weapon, but with all mods it is extremely powerful, even at high levels.
Prior to patch 188.8.131.52x, the laser rifle dealt only 15 points of damage per shot.
The laser rifle does not have iron sights.
Due to the fact that it can fire 2 beams at once by adding a beam splitter, it can score a critical hit for each beam outside of V.A.T.S. This effect allows it to sometimes (with a critical hit for each beam) cause a huge amount of damage (72.6) per shot.
The markings on these rifles as well as their descriptions hint at the types of lasing mediums used in each variant. The 1064 nm wavelength (frequency converted to green, 532 nm) of the AER14 prototype strongly indicates that it is a Nd:YAG (neodymium-doped yttrium aluminum garnet) laser while the ~650 nm wavelength of the AER9 laser rifle indicates that it is likely a Ruby, InGaAs or HeNe laser.