Instead of the "promising results" maybe we can focus on the actual results of the randomized control trial that focused on educational outcomes of OLPC?
That RCT conducted in 320 schools in Peru found:
1. The program dramatically increased access to computers
2. No evidence that the program increased learning in math or language
There's also another difference in that adding a laptop for a kid that is already in school without doing anything to take advantage of the laptop in the teaching is very different from making tablet available for a kid that is not only without access to school, but in a village where everyone is illiterate.
That RCT conducted in 320 schools in Peru found:
1. The program dramatically increased access to computers
2. No evidence that the program increased learning in math or language
3. Some benefits on cognitive skills
Source: http://blogs.iadb.org/desarrolloefectivo_en/2012/03/06/and-t....