I've had the DeWalt "Fat Pack" Combo(drill, recip saw, light, circ saw, 2-battery, and charger) for about 4 years now, and have gotten good use out of them. I would recomend them.
The 18v recip saw works better than my older Milwaukee 110v-ac Sawzall. I am not sure if it is because it is newer with bigger motor, or if having 18vdc has some advantage over an AC motor.
Two things I picked up that are handy... First, an extra battery. When I got the setup, I only used it at home, and two batteries were fine. Now I use it out and about, and like the third battery. Of note though, they are expensive! I thought I'd get a better price at the DeWalt store, but it was still $80.
I also got the 12v-dc charger for the truck. Whereever I go I can always have a low battery charging if necessary. It was about $80 too.
I am not sure how that works... I wonder if it has a charge pump in it to boost to 18v,, or? I know some of the older memory chips in cell phones had charge pumps to boost voltage from the 2.8v battery to the 12v needed internal to the memory chip for the programming of the chips(store phone numbers, ect).