I got this for my 1-yr-old, who cried every time we put her on it. We put it in a corner and let it sit there quietly for a few months to see if she might grow into it. Around 16 months, she ventured onto it again, and she absolutely loved it! She laughs while she rocks and rocks. At 21 months now, she puts a tutu over her head and pretends she's got a cape on, and it flies while she rides. It's a hoot.
The box said for ages 1-3, and I would say that means for ages 1 and 2. My 3-yr-old is petite, but too large for the horse.
Also, the design is very stable, but my little one flipped it backwards a couple times. She's awfully vigorous, though, so I wouldn't think that happens for most kids.