(Image just cuz i thought it looked nice)
Personally, it's gotta be Cool. I've basically seen no one talk about it but the left side of the skill tree lets you solo the whole game with nothing but a pistol or revolver, and cyberware isn't nearly as meaningful as you'd think. You get slowed down time while aiming, buffs to pretty much everything shooting-related from damage to accuracy to reloads, of course you have all the stealth stuff in the middle, and i haven't even looked at the knife throwing side of the skill tree. Not saying it's the best, that has to go to Tech, but it's pretty damn effective for something that seems basically ignored by a large portion of the community.