I’ve never read this one, so when I was in the market for something short last week I just mainlined it. I think overall it’s neither something particularly special nor anything objectionable, except perhaps for the penguins being used as performing animals. There are some rather cute bits with Mr Popper’s pride and excitement in the penguins, and cute/funny descriptions of their performances… and the illustrations are pretty fun.
I don’t really have more to say, though — I bet I’d have enjoyed it as a kid, but it doesn’t have a lot to offer an adult reader beyond a bit of escapism. There’s nothing bad about that, and it filled the hole I needed it to fill, but I can’t exactly gush with praise either!