I adore this. I got into it when I was babysitting recently, at first I was like 'this is going to be a long day' and then after a few episodes I was all like 'I DEMAND TO BORROW YOUR BOXSET YOUNG CHILD!'
The characters are fantastic, the plot isn't dumbed down or patronising and it's just excellent in every way. It kind of reminds me of Doctor Who in a lot of ways, aimed at kids but it has quite an older following too.