A UK review of 14 studies of multiple representations found that gains in understanding and visualization can result from multiple representations, when:
• Software is well designed
• Teachers are skilled
• Students know how to use the device critically, including use of visualization to solve problems in graphing. 
Lower attaining students preferred working with tables, and had trouble moving between symbolic, tabular and graphical forms, depending on the nature of the task assigned.

Goulding, M. (2008). "The role of ICTs in learning algebra: a systematic review." Research in Mathematics Education 10(1): 93-94.