I have the complete Ryobi "plus-one" system. I have every tool they have that fits the batteries.
The older 18 volt batteries were ok , BUT the new Lithium batteries are 1000 percent better. They hold a charge 10 times longer after being charged and in the "ready". The lithium also charge much quicker. I now only have 1 older 18 volt ni-cad battery left, I have 5 of the "lithium" batteries, and they hold a static charge 10 times longer.
Be aware that the new lithium battery has to have the new lithium battery charger,,,, not the old ni-cad charger.
The new charger will also charge the older niCad batteries,,,,but the older charger will NOT charge the new lithium batts. OK??