Lockinfo does not kill the battery. I made sure to set up everything that "refreshes" for at leat 1 hour. But I've used my iPhone 4S with and without lockinfo and I haven't noticed any additional battery drain. I recommend lockinfo to anyone who wants to keep everything organized, greatly expand the compatibility of the stock notification center, and customize and theme the NC to your liking.
I love how lockinfo supports all of the notification center addons in cydia. I use the calendar pro addon as a springboard widget via the homescreen setting in lockinfo. So on my springboard I have an interactive calendar taking up the top half of my screen. Then I have two rows of icons below that (and of course then the dock) and I use one folder via the Folder Enhancer tweak to put all of my additional icons inside specific folders all found inside one main folder. I love lockinfo lol.