I washed my bike yesterday with a bucket, some dish soap, a couple of brushes and sponge. Rinsed the soap off with a garden sprayer. The whole process took maybe 15 minutes. I have a power washer and an air compressor at home, but it's lot more hassle for one bike. For four, maybe the power washer is easier. Only way to know for sure is to do it both ways and see which is easier for you.
I bought a used wheel-set with campy chorus hubs a few years ago that was filthy from sitting in a garage for years and years. I was going to repack the bearings anyway so I decided to clean the wheels with a power washer. I wasn't careful at all and sprayed the heck out of the hubs because they were so filthy with decades of grime and dust. When i took the hubs apart they looked like they had just been serviced, so I would have no problem using a power washer on my bikes if it were easier. I have been powerwashing my off-road motorcycles for decades and the bearings are pretty much the same thing as on a bicycle.