The factors to be considered while buying a blower are Noise Level, Energy used( gas, corded, and battery), and the power of the tool.
Normally 18 to 120 volts is a suitable voltage for a good electric blower.
Yes, the higher the CMF value, the better the performance will be for an electric blower.
A cordless blower with a CFM of 400 to 700 should have adequate power, depending on how it will be used, to significantly simplify your yard work.