The karcher 3300gs machine is fine for short periods of use ,but I would not expect it to be the machine for the heavier useage of work for daily driveway/patio cleaning.Plus with its plastic high pressure hose & plastic lance it would be pron to wear alot quicker than a stainless steel lance
Look for a machine with rubber hoses,brass head, stainless lance, that will pull easily from a drum. It is worth while paying the extra money for a machine that will not work it's nuts off and last you much longer.
The Gerni 260PX is the start of their machines and meets all these requirements
www.gerni.com (for full data/spec)
Gerni also do a 12INCH & 16INCH Floor cleaning head (twin jets RRP 135 pounds & 225 pounds