For the initial 6-12 months of owning my Sans I liked it. HOWEVER, if your filter makes NOISE much more than a white noise sound machine, then you should contact customer service. My FIRST unit was LOUD and I was willing to deal with it on the occasion that it had to intake water. I thought the noise was normal and then it got where I was constantly having to pull off the reservoir and put it back on to get the unit to intake water. I contacted Sans, they asked for a video and immediately requested a warranty replacement for me and sited the noise, which I thought was normal, my complaint had been about having to constantly adjust the reservoir. My second unit is so quiet that I can hardly hear it functioning and I'm amazed!
I researched a lot of RO filters before choosing this one. I would have loved one that also dispensed cold water, but not having that feature isn't a deal breaker. The hot water feature is wonderful and dispenses at the perfect temperature and just takes an ounce or so of dispensing before it's hot. I required that the pitcher with the unit be glass and it's a lovely, lightweight borosilicate pitcher. Most other units I looked at had plastic pitcher and many dispensed from the bottom, which I did not like.
Overall, Sans is a great choice and they stand behind their products. My only regret is not realizing that the noise level was not normal sooner.