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
3. Some benefits on cognitive skills
Source: http://blogs.iadb.org/desarrolloefectivo_en/2012/03/06/and-t....