Re: Potty chairs
This one looks very much like the 1st stage baby bjorn potty bowl. It's very good for training and what's really nice is that it's good for them to be able to sit on it on their own. I would recommend going straight to the baby bjorn potty seat with the high back. The nice thing about this is is that you can take the bowl out so you don't have to be washing the entire potty because sometimes it doesn't fit in the sink, etc.
Also, the high back is good because sometimes the baby likes to lean back and there's something to catch them from falling! And this potty is common enough to find it cheap on craiglist
I hope this helps =)