Battlescribe does the same job, as far as I can tell. It's going through a bit of a transition at the moment since GW asked it to stop hosting any 40k/fantasy files earlier this month, but there's a plan B in place, which is to move to the same system that Army Builder uses, with Wolf Lair providing the software and the community providing the files to use with it. One of the big advantages it has over Army builder is that creating the army files is dead easy.. you don't have to do any programming or edit any text files. This whole thing for Kings of War has taken me about 6 hours, start to finish.
I'd recommend just downloading it and trying it out. It takes about 10 seconds to go ahead and do that with the link in my first post so you might as well.
