Quoted from tomdrum:

They are great, on my 4th one in the last 20 years. I use one in my home repair business often refinishing decks. I've had people think the deck was already stained after cleaning off a decade of crud and then using a chemical cleaner to brighten the wood.
Two tips, do not leave it in a unheated area in the winter. Water inside will freeze and crack the pump. Also hook up the water line up before plugging it in. Then open the wand and let water shoot out for 1-2 minutes before you plug it in. That gets water into the pump and also discharges air. The unit will last longer as the biggest reason for motor failure is overheating.