I'm getting pretty close to level 50 now, so far I'm "Good" in karma but I can change that if needed. I was just wondering how you would rank the level 50 perks, and which one would/did you pick?

• Ain't Like That Now Karma Evil (< -250) Karma reset to 0, +25% AP regeneration rate, +20% attack speed *
  
• Just Lucky I'm Alive Karma Neutral (>= -250 and <= 250) +4 Luck for 3 minutes upon finishing a battle with less than 25% health +50% critical damage *
  
• Thought You Died Karma Good (> 250) +10 Health per 100 Karma; Karma reset to 0, +10% damage *

* All the above perks give immunity to critical hits

So far they all look good in their own way. The "Good" Karma one looks promising if you can max out your karma on the good side...

The neutral one seems like a useless waste of a perk. Extra critical after you finish a fight but only if you're almost dead?

I think it's +4 Luck if you finish a battle with low health, but the +50 critical is constant. Hopefully someone with a GECK can correct me if I'm wrong.

I don't know but it seems the perk should be a bit lower, considering it requires all the DLC's to get it. Oh well, guess its a reward for us New Vegas citizens.

The 50% extra crit damage is constant.

Personally I choose it for that very reason. It gives you THE largest increase in damage output of the three, and anyone experienced with the wastes will tell you you've gotta kill your enemy before they kill you. If you don't utilize sneak attacks or have a low crit % then you might as well get one of the other two.
I'd get Ain't Like that Now if you're a particular fan of the Fast Shot trait, otherwise I'd opt for the good karma one.

Attack speed goodness, very good for unarmed.