I bought these stickers with my grade 5 music class (at an "IGS" in Germany) in mind.
I was never keen on just writing the note names on the instruments nor did I find (with note names alone) ease the learning process for some average and struggling students.
The colours give an extra aid for those with reading/learning difficulties, but it doesn't distract the others. In fact, they all love it! Boomwhackers's colour system is becoming so integrated into music notation software programs like Sibelius, that it was easier using this colour system than making up my own. It's time well saved than trying to make the stickers on your own.
Unfortunately, these stickers come off too easily, which is not good for the regular school system. I would have actually appreciated permanent stickers.
Secondly, some German students get too confused with the English note names, especially in regards to "B" instead of "H" and the sharps. It's too bad there isn't a German (or French etc) edition of these stickers.
I'm still happy to have come across this product.