If you visit this small African country and can visit only one place or one event , then as to my experience – I will recommend to watch the show of Burundi Drummers in Gishora.
While arriving at Burundi in the evening the first place that the ethnic drums were heard, was the beach of Saga and it lasted probably less than 10 minutes. As I reached there by the time that most of the show was over already. And as the reason I was at that beach was looking for an overnight place so , of course , the cameras were in the car and no pictures.
The next day, having spoken about drummers in BurundiTour tourist company, their suggestion was to visit the drum-players in Gishora, those drummers were said to be the most original and the most true ones. And having the best show. The local players and imitators were said to be met at every town.