Ochheuteal beach is the best-known district in Sihanoukville, notably for its cheap bars and many guesthouses.
It is a very young beach with backpackers: in the evening during peak season, the beach is quickly crowded with young people partying. I spent a few evenings there, but I also enjoyed staying a little further away to take advantage of the little piece of paradise that is Sihanoukville.
I think it's good to spend a few days in Sihanoukville during a stay in Cambodia, to enjoy the hustle and bustle of the city centre and around Ochheuteal beach, but it's also important to slightly modify your trip by going to the islands and other seaside cities, like Kep and Koh Kong, because Sihanoukville has the reputation of being Cambodia's "party city."
Nonetheless, there are a few nice activities on the beach, like flyboarding, diving, jet skiing or boating.