Ricky Ricotta's Mighty Robot is one of the best easy readers I have encountered. It is a perfect transition to chapter books with large illustrations and never too many words on a page. However, it is formatted like a thick chapter book making early readers feel very successful as they whiz through the chapters. The story includes evil villains, mighty robots, but also shares valuable lessons about standing up to bullies. With simple writing, the level is good for young readers, but includes subtle humor for adults listening as their children read aloud.
Other features in the Ricky Ricotta series are the 'flip-o-rama' breaks. Following every fourth or fifth chapter there is a section with large illustrations and one sentence captions that can be flipped in animation style action. The end of each book also includes a 'how to draw' section giving simple instructions for how to draw one or two characters from the story. My seven-year-old devoured two of these books in one afternoon and luckily there are at least seven more to try.
Recommended ages 5-8 years.