I have both a great powerful gas power washer I use for pretty much everything you need a power washer for.
I also bought a cheap Ryobi electric from HD with adapters for my nice hoses, guns, etc.
For washing a car you do not need much pressure unless maybe you are rinsing down off-road vehicles.
Gas are loud and stink. Electric is quieter and no exhaust fumes but the best part about electric is that it shuts off when you are not pressing the trigger.
For washing cars I use the cheap electric one 99% of the time.
I have no problem with foaming the cars for prewash but I do have soft water.
Obsessed Garage on YouTube has tested a ton of pressure washers. I recommend watching some of his videos on this topic just for some other perspective.