Some people say they dislike Kenny, but I always enjoyed him despite him being so angry. I always felt his anger was justified since he lost so much, but admittedly, it was seemingly starting to reach a boiling point.
When Jane arrived without the baby, I couldn't quite tell if she got overrun by walkers and the baby died, or if she was intentionally stashing the baby somewhere to get Kenny to flip out. The first thought seemed more logical, but before Kenny attacked her, she pulled Clem aside and said something to the effect of "Watch how badly Kenny loses it here, Clem" (I'm paraphrasing). So it made me think she had planned something. But, at the same time, I'm thinking "how can you hide a baby in a blizzard and expect him to survive?" I'm trying to put all these puzzle pieces together in split seconds.
In the end, I chose to kill Kenny. I agree to an extent with Charger--that it felt like putting him out of his misery. That he really almost seemed to hate to have to be alive. But it was more than that for me. Jane seemed like a more level headed person, and someone who could definitely defend herself, Clem, and the baby. She just seemed more reliable for the long term, especially when the alternative is a broken man with one eye and a slashed belly.
I think, too, that before I pulled the trigger, I held out some hope that maybe Jane just simply couldn't save the baby (because from my past interactions of her, she didn't seem like someone who would remotely let a baby die unnecessarily--she even felt bad for killing a guy who was pointing a gun at Clem earlier in that episode. So I felt that Kenny killing this woman over something he assumed to be fact but that I felt in my heart wasn't fact would be wrong.
I also feel that, in a game like the Walking Dead, you have (or at least want to) make smart calculations of who gets you to "the end" best. And I just felt that a healthy Jane would be better for Clem and AJ's long-term survival than a physically and emotionally wrecked Kenny--as much as I really love Kenny.
In the end, when I found out Jane's ruse, I cursed her out. But ultimately I forgave her and we moved forward together because it just didn't make long-term sense to me to have Clem out in a blizzard, holding an infant, and expect that she'd survive. She needed help.
Got the ending where we went back to Bill's warehouse, see his body, and a family comes by (man, woman, and child). You can either let them in or turn them around. I chose to let them in--don't want Clem to be too emotionally dead inside, lol.