So, yeah, not like many other, I opted for Otres Beach rather than Serendipity Beach when I first came to Sihanoukville. I choose to stay at slightly costly hostel called Mushroom Point.
Back in 2012, USD7 for a 7 round-beds dormitory, USD15 for a private bungalow. Not sure about the price for now. You may check in hostelbookers or hostelworld.
Otres Beach was pretty quiet compare to Serenity. And when I say quiet, it is really quiet. No night life, nothing loud. But it is much relaxing, for sure.
So yeah, my initial plan to stay there for 4 nights ended up to 25 nights as I worked for Mushroom Point as a guests-chef (as a work-exchange) for 3 weeks. Not bad eh?