I actually decided to go with LiFe from experience with lithium batteries in my RC toys. Charger wise, as you can see in the previous photo, I use a quality balance charger that not only chargers the battery, but equalizes all the cells at the same time. I alos think Life and similar batteries are a good way to go with the weight savings and higher outputs. For most folks the cold weather issues won't be either as few of use ride when ti is really cold.
That said, my outdoor power equipment is staying lead/acid.