1. Gas-powered blower-vacs come with everything required to convert the blower into a mulching vacuum. The best ones have a durable, metal impeller that can shred both leaves and twigs. A blower's power is given in miles per hour (mph) and cubic feet per minute (cfm). Cfm is a better representation of the work the machine can do; the higher the number, the more air it moves. Manufacturers list both measurements.
2. Electric blower-vacs need none of the maintenance required by gas engines. The ones in this review allow you to convert from blowing to vacuuming by just flipping a switch. (The gas-powered versions have to be refitted for each conversion.)
3. Cordless blowers move leaves with less noise than gas blowers, have no emissions, and aren't tethered to a cord. They also have less power, so they're best for a quick "sweep" to clean up after mowing.
4. Backpack blowers provide the power and go-anywhere ability of gas without the arm strain of a handheld blower. Backpacks can be used for hours on end without any discomfort; handhelds get uncomfortable after 45 minutes.
The decibel (dB) readings for all blowers were taken from 50 feet away. That's a good distance for the neighbors, but ear protection is a must for the person using any of these machines.