Just remember what others have said; flow is ALWAYS better than pressure.
If pressure is equivalent to speed then flow is best described this way.... which would you rather catch thrown at you at 5 mph (8 kph)? A softball or a bowling ball? 3 GPM or 5.5 GPM? Water weighs 8.33 pounds per US gallon (10 pounds per Imperial gallon or 1 kg per litre) so do the math.
As to what to expect from a supplier? Well, costs vary depending on the ability of the retailer to assist you and their desire to do so. There are pressure washers out there at $3000 and others with similar specifications at $8000.
The difference is whether or not they are local or elsewhere? Are they supporting all warranty or some? Is there a loaner available should the need arise? Do they stock common service parts to get you back in business right away? Are they using the best possible components to give you longer life and shorter lifecycle costs? (Cheap parts break down more frequently requiring more frequent replacement; therefore false economics) Is the wiring/ plumbing etcetera of adequate size and performance for the desired performance of the machine? Does it meet safety certification standards (not just conform to but actually paid for and tested to meet or exceed the standards)?
In other words, how would you feel about a customer of yours going on to the internet and getting all of the components they need from somewhere else to do the job you are doing for them?
Dollars spent outside your community never return to your community so needed funds for road repair or park maintenance may not be available. If your local retailer goes out of business how will they sponsor your child's soccer team or have the ability to continue coaching it?
All things considered you need to look at the TOTAL costs of doing what you want. A poor craftsman blames their tools but buying inadequate tools will give you cause to blame someone/thing.
Hope this helps? Cheers.
