From my experience, Institute weapons are rather common. More so than the Gunners who are the main source of laser weapons that i've seen. the damage on them was about on par with other weapons, just a few points lower than a laser weapon or a ballistic weapon... until i took rifleman, now the difference is much more noticeable. i did mod out and play with an institute rifle and it seems like it has a point where it pulls ahead, the science rank 2 or 3 perk allows it to have an equal or better damage than the same rank of laser i think. it also fires as fast as i hit the trigger with very low recoil and great accuracy. it worked great as a close to mid range weapon until rifleman and a combat rifle started to really outclass it.
From a setting perspective the Synths normally encountered are perhaps meant to be somewhat disposable and knowing that their weapons will end up in the hands of enemies the institute does not wish to let their best tech fall into the hands of others? also as said, mass production and such. perhaps there was a lot of ground to make up when switching over to primarily plastic based components?
Otherwise i like look of the weapon and the blue beams much more than traditional laser weapons.