Soreike! Anpanman (Let's Go! Anpanman) has been airing since 1988, and it's still marching on. It's not hard to see why.
The animation is outstanding; the sheer simplicity of Anpanman's design is just so cute! Everything (and everyone) is smoothly drawn, no rough details, and his world looks amazing.
As far as sound goes, it appears that some sound effects were later used by the 2005 Doraemon series on Terebi Asahi. I'm not marking it down for this, I'm just pointing it out. Voice acting is great; Keiko Toda (Anpanman) does a great job of voicing the character. There's also a lot of variety in their voice ...