my dd was just 2 when ds was born and had only been walking since 19/20 months so i decided that it was too much to ditch the buggy just yet and got a double, although previously i had been v. against them. However now she is 2.10 she is walking more confidently and will walk further as i dont drive this is important.
but..........it depends on the child. and the season! i had a worry about a buggy board as ds was born nov so if dd was on the buggy board for any length of time she would have been soaked as no rain cover and she wouldnt have been able to hold an umbrella as i wouldnt have been able to push properly!
it all depends, jsut weigh up the options, i think each works well for different people!