your best bet, since there is a 3 tier choice now, fuel, non fuel, and brushless, - is to head over to milwaukee's website and just compare torque specs and see how much of a difference there is.... i have both.. the fuel at home, non fuel kit at work.. they are both great and you will be happy with either..
if your intentions are just for driving screws, the non fuel will be fine.. if you think you might want to do some bigger stuff like lags, maybe the fuel is worth it.. idi imagine the brushless specs are right in the middle.. i didnt need the fuel stuff for home, i just decided i wanted it and thats what i went with..