“How to: Select Cordless Power Tools”
Summary: Unless your intent is to only use a cordless power tool now and again and only for a very short period of time, always opt for the higher battery voltage, more expensive, cordless power tool.
Cordless power tools really are a neat, handy invention.
I am not sure but I think the cordless electric drill came first (also used as a screwdriver) and now cordless circular and reciprocating saws, sabers and small portable vacuums are also available at your local hardware store.
From my experience, I have only one piece of advice to offer. If you only want to use the electric drill or screwdriver for a screw or two now and again, it does not make much difference what make or model you buy. However, if you plan on using the cordless tool for some length of time and perhaps screw in 50 screws, buy a unit with the largest battery voltage you can find.
The first cordless electric drill I ever saw as a 9 volt rechargeable. This drill would screw in perhaps 10 screws before the battery attached to the drill was exhausted. A toy.
My current cordless is a 19.2-volt and it pretty much does any job I want it to do on one battery but I also have another battery being charged all the time.
So, it is probably a matter of intended usage. Use a little, it does not matter, use a lot, get a high voltage unit.
Oh, one final note, I have found the cordless circular saws, and other cordless tools to be pretty much of little use. The tools are just not designed as sturdy as a real, corded tool and again, the endurance of the attached battery is an issue.