We have used these with my son very successfully, but in a homeschool setting, not a typical classroom setting. Voice recognition software can sometimes be a little tricky to use with younger kids, as most of the software needs to be "trained", and little kid's voices and speech patterns can be pretty variable. Keyboarding was by far the better choice for our son, as then he didn't have to go back and edit out all the incidental comments that he would make to himself while composing. I'm thinking that VR wouldn't be the best choice for in-classroom work, either, because of the need to speak aloud and the probable interference with and from others. You might want to spend the summer getting your DS as fluent as possible on the keyboard.
