I took delivery of a new Duster 4x4 diesel in January 2018 and it has been a pleasure ever since. This was a downsize from a 4x4 Raider Double cab after the chickens flew the coop. The deeper, the softer, the dryer the sand is, the better! Absolutely unstoppable. It is not as happy on jagged rocky tracks as there is no low range. Creeping forward at walking speed can be challenging when the revs drop too low.
The tyres that were fitted were rubbish and all (including the full-size spare) were replaced within the first 5000km. Apart from normal wear and tear items, I have had very little trouble. The turbo went at about 90000km but was replaced under warranty. I am on my 3rd set of rear shocks. The experts say it is because I overload on long expeditions and 'bottomed-out'. I routinely take out the back seats to make space for camping stuff and this might be possible.
I can't comment on the availability of genuine spares. The turbo replacement had to be imported (3 weeks) and Renault didn't have rear shocks in the country so I went for 3rd-party ones. I have been inside four Renault workshops and my only advice is make sure you find a reputable one. Three of the four I visited were shocking, both equipment-wise and technician-wise.
Earlier this year I thought of donating my Duster to a child and getting a later model. It seems that imports of the 4x4 stopped in 2019 so I could only get a one year newer model. Looking at various second-hand car websites it quickly became clear that there are very few of these in circulation. There were only four on the WeBuyCars site. So, I have decided to stick with what I have and look after it. 121 000km done and still going well @ 6.2l/100km, if I drive carefully.
You are welcome to contact me if you have more questions.