Boat from Siem Reap to Phnom Penh

There is a speedboat operating between Siem Reap and Phnom Penh on the Tonle Sap lake. This seems like a cool idea but you should spare yourself the hassle. The boat sells more tickets than seats, resulting in arguments between passengers, some of which eventually end up sitting on the roof next to the noisy engine. Since the Tonle Sap lake is very wide there's nothing much to see besides a floating village of Vietnamese refugees. What's more, taking the highway around the lake is actually a lot faster !

Below is part of my travel journal.

Today we took the boat from Siem Reap, across the immense Tonle Sap lake, back to good old Phnom Penh, were we would continue our journey by bus to the coastal town of Sihanoukville. Quite a bit of chaos erupted in the boat since the boat owners had given out double tickets for seat numbers (seemingly this happens every day). Some really nasty discussions with a couple of French followed but eventually we decided to let them have their way (after all those 'sympathetic' people never give in, do they ?). BJ had warned me about the boat, which always sells more tickets than seats so the last passengers have to ride on the boat's roof for several hours. We were lucky though as we all had reserved seat (not counting the French incident) and had a rather comfortable trip to Phnom Penh in the boat's air conditioned front cabin. Strange enough, the trip to Phnom Penh actually takes longer by boat than by bus, as we found out because the busses that had dropped us off at the boat were already waiting for us in Phnom Penh.

I agree with the review Ed gave, but will give it a different star rating.
When I took the boat it was loaded beyond the point of safety. There are about 100 seats on the boat (inside) but at least 40-50 people had to sit on the roof throughout the journey, without any proper rails to hold on to (and the boat is quite fast). And I for one didn't see any life vests aboard.

People will tell you there is no regular bus service between Siem Reap and Phnom Penh, but there is. People will also tell you a bus will take ages because of the bad roads - it won't.
The new, smooth highway between Siem Reap and Phnom Penh is finished, and taking the bus will not only save you a lot of money ($ 4 vs $ 25) it will save you a lot of time too.