the 14.4V is a bit hungry on the batteries I have to admit am I right in guessing it's more the 14.4V thats the ball arch when needing a charge, currently I haven't been using it as much as it's my back up drill got a 10.8v Pro tool drill much lighter and longer battery life, though i didn't buy it because of the Hilti being that bad, It was just I had to have this seasons new tool. The 36V I find on a hard day drilling preformed concrete with a 6mm bit I can get away with 2 charges a day but it's all subjective anyway, does anyone else have any other brand onsite just as a comparison.
Jack maybe take a look at one of the Hilti centers they have all their gear and you can try it out there and then, I know this doesn't give you a direct comparison but it's a chance to get a feel for the tools. You will never get a definitive answer from anyone as everyone has a different opinion only you can make up your own mind. If getting a hands on comparison fails just compare manufacturers stats to narrow down the choices. Sorry it's not much more help.