My friends and I stayed in two double rooms for 3 nights. The rooms themselves were clean, and included everything you needed. You may or may not get a bath (there appears to be a shower in every room) but you probably won't get time for a bath!
The breakfasts were large and delicious (baguette, fried egg and fruit). There was free wi-fi, but it was fairly non-existent in the rooms. You have to go down to the lobby to use it, which for me was fine because while doing so I got to chat to all the lovely people there.
The best thing about this guesthouse, though, has to be the staff. Mr Bun Kao is a lovely man, who is doing a lot to help the community. Every other member of staff was also very friendly and helpful, and had a decent command of English.
I highly recommend you request Kouch, a guide and tuk-tuk driver to help you out. He was our guide for 2 days and showed us an excellent time. He is fluent in English and French and his knowledge of Cambodian history and all the temples is astounding. If you come to Siem Reap with no plan, like we did, entrust yourself to him - he will show you everything you need to see! If you have a plan, by all means tell him about it and he'll make it happen.
I had a fantastic 3 days here, and if I'm lucky enough to visit Siem Reap again will definitely stay here!