PSI isn't everything until you get down to really blasting surfaces. GPM matters to as it equates to volume of spray water put on target. High PSI with low GPM will scar concrete but take forever to clean off a driveway. Moderate PSI and better GPM gives you both a powerful (enough) spray and enough volume for a washing effect. Most homeowners would be well served by something from 2500 to 3000 PSI. I own a 13 hp Honda unit and it pushes 4200 PSI with lots of volume. Triggering the spray gun produces recoil and takes energy to manage during lengthy cleanups.
My wife is wanting us to get a unit for our home (she can use if wanted) and my current favorite contender is the Echo (Bear Cat) PW2700. It has a Honda engine and is widely regarded as a great unit. I can buy one locally for $475.
Stihl does offer a nice lineup of washers, but their gas powered units use Kohler engines. If I'm choosing between Kohler or Honda, it'll be the Honda every time.
If I was looking at a new pressure washer I'd probably try and grab one from Harbor Freight on sale. The Predator engines are Honda clones and seem to get positive feedback everywhere. I was thinking about piecing together a washer with the Predator engine but couldn't do it for much less than the turnkey unit.
If you go gas use startron and swap out the gas every now and then. I don’t use mine often but I run it at least every spring regardless of usage to make sure the seals don’t dry rot.