UPDATE 2: Almost 1 year of use This is still going strong. Slight discolouration on the nossle, but it still works perfectly and the pressure holds fine. As stated, I use this for alloy wheel cleaner so fairly corrosive stuff. Brilliant quality!
UPDATE: had this for 3 months+ now and the nossle still looks brand new with no sign of wear or corrosion. Given I'm spraying alloy wheel cleaner (some acid based, some alkaline) this is a good indicator the sprayer will last a long time. It also still holds the pressure perfectly fine.
I've had a few of these in the past and all suffer from issues either with nozzle corrosion or from pressure leakage, however this one is so far suffering from neither and is a great quality product. I use this for alloy wheel cleaner where dilution ratio is up to 10-1, but 5-1 is best. I fill to the 0.1 line with concentrate and the rest with tap water. I then pump and spray and everything just works as required. Pumping when full is quite difficult, but is ok (pump enough to spray 2 full wheels, then pump again for next 2). I've not had it long enough to see if the nozzle will suffer from corrosion over time, but it looks very high quality so I'm sure it will be fine. I will come back and provide an update after a few months of use. All in all, this is a great quality item, great value for money, and would have no hesitation in buying again.