I've lead many groups of people on trips to the temples around Siem Reap, and I always start our adventure with a stop to this museum. If you give yourself an hour here, you'll at least have a basic understanding of the history of the Khmer Empire.

The museum has several floors, and my advice is to start at the top, and then work your way down. There is a nice gift shop on the bottom level. There is also a bathroom you can use before you head off to the temples.

They will ask you to check in any backpack or large purse, so I recommend keeping valuables on your person.

-- John Shors, bestselling author of Temple of a Thousand Faces: A Novel of Angkor Wat

We haven't seen the temples yet but went to the museum today, I'm glad he did because we got a good amount of information, background and history on the cultural significance of the temples as well as Hinduism and Buddhism in general.

The $12 USD ticket and $3 USD audio book were well worth it, the audio book in particular gives you much more in depth stories about each section. The audio book and the multimedia presentations and that of the exhibitions tend to overlap and repeat themselves quite a lot, we found ourselves speeding up through the last 2-3 sections after dawdling and soaking in the first 5-6 section taking us over 3 hours.

New facility is well designed for the collection and offers a nice overview of the objects / architecture in the ruins. Do not think this small museum in any way replaces journeying to the Wats. There are several films throughout which provides interesting information on specific topics or locations. The museum story is large and has a wide selection with interesting books. There is a small coffee and juice cart but no proper cafe. I wouldn't say this is a "Must" during your visit to Siem Reap, but it is a good stop one afternoon when you get back from exploring the countryside.