I have used these harmonicas to teach children music for years and seeing their faces light up as they play a tune after only a few minutes of practice is PRICELESS. I think that school music classes should be using them as a first instrument. The big holes are really easy to play even for very young students (5-6 years)
However, VERY IMPORTANT, I originally bought two of these harmonicas with a four-color system (hole one was marked red, hole two blue, hole three green and hole four yellow) which I strongly prefer to what the newer harmonicas have. So what I do is simply stick a little red, blue, green and yellow sticker in front of each hole and then I can write tab for the kids with colored arrows. Red arrow up = blow first hole, red arrow down = inhale first hole, etc. With only four colors to worry about it is much easier for me to write music and for the kids to read it. The lack of this four-color system is why I rate the features at only 3 stars.
If you want to give your child a great introduction to music and know enough to write out a simple tune then this is a wonderful choice. They are so inexpensive and I have NEVER had a kid that didn't enjoy playing them.
One more thing, I wish that they would let you select the color. My little boys aren't too crazy about the pink and yellow ones.