DD just got one for Christmas so she has only used it once (her uncle took her outside when he gave it to her and helped her with it). He had to push her on it. I don't anticipate it really being used much until springtime anyway, so we'll see how she does with it then.
Re: Anyone have a Balance Bike?
DD took a month or so, but she learned first to pedal on a trike. DS took about a minute, but he has always refused to pedal.