Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Cheaper than buying batteries

This unit is nice because it saves money on batteries and allows more play time. The only drawback I found is that it does not stay on the cradle when charging very well. It will be fine if it is on a completely flat surface and it is not bumped. It is also important that the kids don't run around nearby or it will fall of the cradle from the vibration. It needs some sort of clip to hold the gameboy advance in place, if it had one it would be 5 stars. I gave this item 4 stars just based on the cost savings alone, it is worth it.