Is a beast!! With the grunt perk and 100 guns skill, with the hand load ammo. So many one shot kills with that thing on legion, ncr or regular folk. Honest Hearts is on the short side in terms of game play length, but the loot you get from it sure makes up for that. This gun, the silenced .45 pistol, Survivalist Rifle, Desert Ranger Combat Armor and Joshua Graham's armor (only weighs 8 pounds!!) is some serious sweet loot. I'm not a melee character, but theres tons of that stuff from the DLC too.

the 12.7mm pistol is good to

I'm gonna compare the A Light Shining in Darkness and the 12.7mm Pistol, for no particular reason, I just want to:
DAM:
ALSD- 33
12.7mm- 40
DPS:
ALSD- 144
12.7mm- 110
Crit DAM:
ALSD- 33
12.7mm- 44
Crit Chance:
ALSD- x2
12.7mm- x1
Fire Rate:
ALSD- 4.38
12.7mm- 2.75
Spread:
ALSD- 0.55
12.7mm- 1.1
AP Usage:
ALSD- 15
12.7mm- 17
Ammo Capacity:
ALSD- 6
12.7mm- 7
Reload Time:
ALSD- 1.67s
12.7mm- 1.67s
Skill Req.:
Both- Guns 75
Item Health:
ALSD- 250
12.7mm- 80
Weight:
ALSD- 1.2 lbs
12.7mm- 3.5 lbs
Value:
ALSD: 4500
12.7mm- 3991

Don't think I'm biased about these two weapons..........maybe I am, but still, I'm just giving information from the Vault, so yeah.

Both awesome weapons but the Critical Multiplier for ALSD means its geared more towards characters with an affinity for critical hits. The Silenced 12.7mm is more for stealth characters which are really the only ones who use Luck and such so honestly it comes down to more of a personal choice/Character Archetype.