Rule of thumb, never buy one with a vertical shaft engine. Second rule of thumb, always buy a Honda/clone engine. Why? Because any part you could ever need is literally a few dollars on eBay. Carburetor? $10 New coil? $10. Third rule of thumb, never, ever buy a Suburu small engine. Why? They are well built, sure. Carburetor? $150 New coil? $150. They are incredibly expensive to keep running if you ever need to buy parts. So expensive in fact, that it usually is cheaper to REPLACE the engine than to repair it. I ran a small engine shop. Almost every time someone brought a Suburu in, they were NOT going to like the news.
Vertical pumps are rated at 50 hours. ALL of them. Even the cheap horizontal pumps are rated for 300 hours.
So my general advice at the entry level is to always buy a Honda GX200 or clone, with a horizontal pump.
I've used/abused one of these for years and I highly recommend them. Use the 20% off coupons to make the price better.
Has a Honda clone engine.
https://www.harborfreight.com/3100-psi-28-gpm-65-hp-212cc-pressure-washer-epa-iii-62200.html
The good thing about the above combo, is that if the engine ever dies, a brand new engine is only $100. You can fix your pressure washer yourself, for only $100. If the pump ever dies, the cheaper pumps are $100. Again, you can repair it yourself, for only $100. If the carburetor corrodes away, and needs replaced, its only $10. See my theme here?