steven, i have 2 of the c12.my first one i got was the 3.0ah nimh,then i got the c12 2.4ah nicad.i use them both every day.as far as power goes,i can't tell the difference.the 3.0ah is suppose to last longer but it doesn't really matter.after all with 2 c12 4 batteries and 2 charger, i'm allways charged! the only thing i can tell you about the nicad is that they have a tendecy to build a memory.i'm not a battery expert,and if you are not familiar with that i recommend that you look it up on the internet.(it's when you put the battery in the charger and the battery thinks that is full but it's not).the 3.0ah nimh doesn't suffer from that problem as much,so it suppose to last longer.i install cabinets,and sometime i build cabinets/bookshelf/built ins,so 95% of my time is on site.if you just want a drill for your shop/garage than the 1.3ah will do just fine, but consider the 3.0 if you work on site.hope this helps!