Definetely get the gas.
Any box store 120V plug-in pressure washer is a pain. Biggest problem is plugging them into a big long extension cord at too light gauge of wire. These things are drawing a minimum 12 to 13 amps if plugged directly into the wall, add 50' of extension to get the thing to where you need to use it and the thing will overheat, trip thermal overloads or the breaker in your box. Even if you do get it work OK on the cord you have, the motor runs too hot and shortens it's life span. The cost of a decent 12 gauge extension cord of any length, may be as much as the pressure washer itself.
The gas machine will go anywhere, limited only by a water supply. With a proper foot valve suction kit, you can even draw from the lake if need be.
One thing to consider on any pressure washer, is not only the pressure, but more important is the flow rate. 1200 psi at 4 gpm will clean much better than 2400 psi at only 2 gpm.