My partner and I did a two-day tour over new year with Leak, a member of the Angkor Wat Services team. The tour was excellent - even better than I had hoped, and worth the money.
Chet was very helpful when I was trying to set up the tour beforehand, and he was able to quickly answer all the questions that I had via email. We wanted to check out the sunrise over Angkor Wat on the first of January but avoiding the crowds if possible, and it was easy to arrange this. He also helped me work out the budget that we needed.
Most of all, it was invaluable having someone as knowledgeable as Leak actually being able to come in to the temple complex with us. So while you can do a similar tour for cheap in a tuk-tuk, you will absolutely miss out on understanding the meaning and history of the beautiful temples when the drivers wait outside. Leak's English was great, he had a good sense of humour, and he really helped us get the best out of our short stay in Siem Reap.More