In March 2013, we bought a refurbished Boot Scoot Zoomer balance bike from a local bike shop. Our eldest, now six, didn't started riding a bike until she was five and struggled for over a year to learn. We got the Zoomer for our two year old because we wanted to get him started at an earlier age. It worked so well for him that we took the pedals off of our six year old's bike and that sped up her learning process. She now rides with pedals and without training wheels. I highly recommend this balance bike because it has been easy to use and safe to ride.
Our two year old has loved riding his Zoomer from the first day he got it. He is able to get on and off with ease. We started him on sidewalks and going down hills to give him a chance to experience momentum without needing to use his feet to push. After 10-12 outings, he seemed to have it mastered such that we didn't need to be by his side at all times. Since, he has continued to expand his skills to include self-propulsion using his feet, cornering, and controlling his speed. What's more, adjusting the seat height has been easy and the airless tires have worked well.
Our two year old has fallen many times while riding his Zoomer but has yet to get hurt. The handlebar edges are securely protected by soft round grips. In addition, the bike's low profile means that all falls have been only a short distance to the ground. Lastly, he has learned to safely slow himself down as he approaches street corners and intersections; although, as a precaution I still manage all street crossings.