Re: Lightning Reed vs. Electric Peashooter?
For Lightning Reed the chain reaction is limited to a specific amount of Zombies, depending on its level. Since Electric Peashooter's Peas pass through the Zombies the chain reaction is not really limited to the number of Zombies.
Electric Peashooter is an upgraded version of Lightning Reed. There are a bunch of videos that compare the two plants. Here is an example: