When we first tried this show (at the recommendation of the kids' daycare provider), I thought it was darling, and I was pushing for the kids to watch it constantly. I'll admit to being a little bored with it now (and I think the kids feel the same), but I still think it's a very good show that teaches kids a LOT.
I love that it's so educational. The characters are cute and all, but I'm most impressed by the wealth of education and even life lessons it puts out. With everything from letters, to spelling, to phonics, to plain ole good values ("Tell the truth")--this show is one of the best I've seen, education-wise. It beautifully reinforced what my daughter was learning in daycare.
It can be a bit on the boring side, but the characters are very cute, and the education can't be beat. I definitely recommend to ALL small children.