I've ran both and personally, unless you're using them in a remote location in which you need a water tank, I don't have any time for a gas powered pressure washer. Reality is, if you have water access you usually have access to electricity also. As far as cumbersome, the water hose is far more cumbersome to work with than an extension cord and you don't have to worry about carburetors, fuel, oil changes, ect. The electric ones also have a pressure limit switch as if you let go of the handle, it pressures up and shuts off and fire's up as soon as you pull the trigger and start spraying again. This is really handy if you're stopping to scrubs stuff with a brush, or squeegee a section of a garage or shop floor, etc where you aren't continuously pressure washing and you have some stop and go. With the gas powered, you have to shut it off and restart every time you stop for more than a minute or two. They're also not nearly as noisy and you can use it in a confined space without having to worry about gassing your self with exhaust fumes. One other benefit of electric, there's not hot exhaust to melt your hose when you inadvertently drag it across and you don't have to let it cool down before you put it away or lean something else against it.
I know many have mentioned that you can't get the pressure a gas model puts out in electric which is entirely wrong, however you will have to pay for it and depending how much pressure and volume you want, you may need 230/240v which not everyone has available. That's really the only down side. A good commercial electric unit is gonna run you $700-$1,200 pending options, pressure, volume, ect. you can get really crazy and get into units in the $5k-$10k range but I don't thing that's what were talking about here. Dollar for dollar, the cheap gas one will outdo a cheap electric one. Get into the bigger more commercial type units and the sky is the limit for electric. The biggest downside I've found is there seems to be a serious price gap on the electric ones, you find the cheap homeowner models for $100-$300 and if those won't cut it, the next jump is up around $1k. Food for thought.
One other thing to keep in mind is the GPM rating. it;s not just psi that gives you cleaning power but also how much volume your spraying.