I have the Rockabye Baby CDs for NIN and Tool, so I thought Nirvana would be just as much fun. However, these songs were scary. I'll be playing this as my Halloween music. Honestly, most of this sounds warped and evil. It's probably because Nirvana did not write very complex arrangements - most were basic and fast, and it sounds like murderous clown music when slowed down and music-boxed.
I won't be playing this for my little one, but it is very effective mood music if you want to terrify someone.