Set off on time, but made multiple, long stops within minutes of leaving. We finally stopped stopping frequently after a couple of hours. With stopping half an hour for food also, we arrived in Sihanoukville 1.5hrs after the stated arrival time, and to a different location than stated.
OK service but be careful, they have 2 bus stations in Pnom Penh and 12GoAsia only shows one of them on their map (the central one). Apparently our bus departed from the other station (near the airport) so we had to get up earlier & take a 45 minute tuctuc in order to catch the bus in time.
The bus was also 30 minutes late, by the way.