It is hard because there is no one-size-fits-all. Sometimes, a soft-paced, online math program can be exactly what a child wants and needs. Other times it can be totally boring, and it is just putting a curriculum online, which can make you lose the human element.
Teachers should ask students whether a program is a meaningful use of technology or not. Teachers should trust their students about things like this because the kids know.
In our experience, if you give them a say in what they want to learn, they will give you valuable feedback and tell you if something was a worthwhile tool or not.