I slept for two nights, or tried to. The dorms had many beds, around 16 I think. I slept poorly, although because of fellow travellers, not the hotel. The first night other backpackers came back at 3 am shouting completely drunk (and one so sick he made loud noises for a long while after that). Not the fault of the hotel, but a bad experience anyhow. The second night there was a scooter from somebody at the hotel whose alarm kept on ringing.
Staff friendly during my stay, except that when I checked out the guy at the reception did not believe I had paid him the first night as soon as I checked in, as I was planning at first to leave very early the day after. So we had to discuss for a while, until he finally accepted with an unpleasant "yeah whatever".
Dorm for 5$, good price for Luang Prabang, but 20$ for a single room is definitely too much. I found much better for half that price.