Long ago I had a really good electric washer. Such things have existed at some point in history, but the ones you see now are generally pretty lousy. In addition, good or bad, the electric washer limits your mobility. A pressure washer uses so little water volume that you can run it from a hundred feet of hose without losing pressure, but long extension cords are a nuisance, and you risk voltage drop. Newer electrics have GFCI plugs, so they're pretty safe, but it's still a nuisance.
If you have limited space, and no outdoor storage for a gas machine, an electric washer will work way better than nothing at all, but if you can, get a gas one, preferably one of the ones with a Honda engine and replaceable nozzle tips. The adjustable-spray plastic wands are easy to break.