A Plasma Rifle is the exact opposite of a Laser Rifle. It requires the Microfusion Ammo which can be bought from traders, scavengers, and on Brotherhood/Enclave Soldiers therefore making it fairly uncommon. Plasma Rifles are stronger and much sturdier than the laser rifle, but the slower rate of fire and the short range of combat you have to be in really does come in to mind when having to choose between the two. They are worth more and they aren't exactly easy to come by as most are in pre war armories gaurded by sentry bots, or on Enclave Soldiers; the exact opposite of the Brotherhood of Steel Soldiers. In this sense it is worth more to sell it off if in good condition and go for a Laser Rifle instead due to the rarity of the Plasma Rifle. The Laser Rifle is also much cheaper and much easier to repair, and many can be found in the wasteland due to mass production back before the war. In short, if you want to take down a raider at 50 meters and you are willing to sacrifice damage to take him down quick before he shoots you, go for the Laser Rifle. If you want to take him down with a plasma punch that will kill him quicker then go for the Plasma Rifle,but just try not to miss. One thing though, because the Plasma Rifle's projectiles go so slow you will have to fire the shot quite a bit at closer, just to insure you get a hit on the enemy, making the Plasma Rifle a pretty fair mid-close range weapon, not a long-mid range weapon as the Laser Rifle is. The Plasma Rifle is a great weapon to use in short range combat and any critical hit will disintegrate your foe, turning them into gooey green slush.