Electric presumably? Kranzle.
They arn't cheap nor are genuine parts but they are on top of the job and they last, expect to have little if any change from a grand, if you go for an upright with auto stop and pipe reel etc you'll be over a grand, i have the 1152tst, had it for maybe 6 or 7 years of regular use, had it serviced by a pro this year.
The reason i went for one, had numerous cheap and not so cheap domestic use types over the years, none really up to much and all packed up in short order, but had a chat with the cheap who serviced our industrial steam cleaners at work for advice.
You want high LPM water flow, 7LPM minimum, high pressure with poor water flow is useless and likely to cause damage to what you want to clean.
Brass pump and fittings, the cheap ones are almost all alloy which will eventually corrode.
Rubber pressure pipe, not plastic, 15 meters is ideal for car and driveway cleaning i've found.
Once you've got those three things and a 15 meter pipe with pro quality gun and lance you'll be knocking on the door of a grand with any make, except maybe Chinese made.
Many detailers/ valeters use Kranzles.
If you find a better overall make, let us know please Frank.
Couple of tips.
Keep an eye on the oil level and change the oil periodically, i use chemical through the machine and after finishing with the chemical i run some clean water through the chemical suction pipe.
If you spend out on quick release fittings make sure they're either brass or stainless steel, some of the cheaper ones are steel so will rust inside and those little bits oif rust will block the jet, not a big deal to undo and clean out but best avoided.
Some (not sure how much to spend before you get this) Kranzle machines can suck water from a water butt etc if that's of any use, not sure how much level drop they can do this from though, mine is capable but haven't used the feature.