This is an interesting museum. It definitely has a great variety of musical instruments from many countries, and mostly of older eras, with musical content you hear by way of headphones.
It's extremely educational, and will take most of a day to fully tour.
The downside I experienced was that a large group of school children came for a tour - which is great - but they were extremely noisy and one couldn't hear the music content on the headphones. The museum was unusable for the 1.5-2 hours the children were present.
My advice is if you are planning to visit this museum, call ahead and see if there will be any groups like this when you may visit. Plan your visit around them and you won't have a major distraction.