Not too far from the main temples of Angkor Wat, Ta Prohm and The Bayon but usually much less crowded. There aren't too many beggars or hawkers either so it's generally a good temple to visit if you like a bit of peace and quiet.
The main building is rather like an Aztec Pyramid and you can climb the steep stairs all the way to the top for a great view of the surrounding countryside. It IS very steep though and climbing down can be a bit of a challenge - not for people with vertigo! It can get very busy at sunset.