I stayed at the Phousi Hotel the first time about 5 years ago. It seems like not much has changed. I didn't experience any problems and the staff was nice and informative. The rooms were clean (for Laos standards), but were just dated and old. The Phousi is located in the heart of Luang Prabang, right next to the night market and has nicely manicured grounds where one can enjoy a nice Beer Lao. Its a great starting point to begin the day or evening. I had a last minute booking for a standard deluxe room that cost around $65/night (Christmas time).
Luang Prabang itself has vastly developed unfortunately the Phousi hasn't, the hotel has remained the same since I was there, not much improvement. In fact, I would say the location is now a hindrance if one is looking for quiet and serenity. There is constant noise. Its located on the main artery road with traffic noise starting from 6AM and lasting till 12AM. In addition, there is a primary school located right behind it as well. So, if you are there during the afternoon or early evening there will be kids screaming/playing.
The hotel purported to have WiFi, but I could never connect to it. Other relatives at mine stayed at different, vastly more expensive guesthouses, and their wifi didn't work either. So, it could be something with the Lao network.
If you are looking for a good central location the Phousi is good. If you are looking for charm and quiet then better to pick elsewhere.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC