Gas models have one huge advantage in pressure washer reviews: They clean faster, due to much higher pressure and flow rates. They can handle any job a homeowner can throw at them, including heavy concrete cleaning.
Electric models have all the other advantages. They're much smaller and half the weight of a gas machine but check out electric pressure washer reviews to find the best electric power washer. They start up as soon as you squeeze the trigger and shut down as soon as you let go. So you won't have any gas hassles or starting issues, and you'll never have to worry about pump damage from extended idling. And since there's no exhaust, you can use them indoors.
If you need maximum power and want to get the job done fast, go with gas. Otherwise, enjoy the convenience of an electric pressure washer.