Okay, to be fair, there's no such thing as a luxurious hotel in Ruyigi (and possibly anywhere outside of Bujumbura, for that matter.) It's a tiny little town at the eastern edge of Burundi, near the Tanzanian border. However Villa des Anges is the best place to stay in Ruyigi.
Each room goes for about 15,000 BIM and comes with a desk/workspace area, tiled flooring, showers with hot water, a TV, a closet, and plastic shower sandals. There are screens on all the windows, which means that one can have air circulation without worrying about mosquitoes entering.
Like much of Ruyigi, this hotel is owned by Mme. Maggie - a formidable woman who opened her heart and home to about 200 children orphaned by the war. Some of her (now adult) children run this hotel.
The staff are all very nice, speak French without difficultly and offer great service. A breakfast of tea or coffee, an omelette and bread is provided for all hotel guests and comes within a few minutes.
The hotel is situated in an expansive garden and is usually quiet. There are a couple of drawbacks to this place though: (1) It's next door to a mosque and the namaz begins around 4:30/5 every morning. Because the windows in the bathroom have only a screen on them, I'd recommend closing the bathroom door before you sleep at night, so as to block out some of the noise. (2) There will inevitably be holes in the mosquito net, so bring tape or safety pins to keep the net critter proof.
One final tip: Since it's the best hotel in town, there's often limited availability, so reserve ahead of time.