I'll echo your recommendation for walking bikes, and progression to islabikes.
Ted started on a generic balance bike when he was coming up two. He didn't really get on with it at first, but we left it with him and he soon started tearing around the house on it. We had a sweet spot about 3 months after his second birthday, where he could ride on the bike at adults walking pace. We took him to the shops most days on it. Having learnt how to navigate doorways and the cat, his low speed control was pretty much perfect.
Towards the end of summer, we couldn't keep up on foot. I'd chase him to the local park on Panzerfiets. Ted is two and a half in the video below.
For his third birthday, we bought him an Islabike. Although he could balance on it from the outset, it took him 3 months to accept that pedalling might be faster than running astride it. After playing on a tricycle at the local dads club, Ted said "take me home" and mimed a pedalling motion all the way back with his hands. When we got home, I took the video below. His first time. 3 years, 3 months.
That evening, he put in a mile and half tour of local friends. He logged over 300 miles with me by the time the summer drew to a close (most of them are tagged in my mycycling log account!). His balance bike has gone to another cyclechatter.
Now his younger sister (Darcey) has a balance bike of her own. This is her at 17 months.
I'd offer the following tips, that are less to do with "which bike" and more to do with making a success of whatever you choose.
- Ride with them, and let them see you ride. They want to copy you.
- Try to avoid using the car for local trips. When we integrated cycling into our daily routine, both kids really began to pick things up quickly.
- Resist the pull of stabilisers. There are kids in my street who are still on stabilisers, and are coming up 6.
Andy.