Even though What's Michael? is obviously very popular in Japan, I hadn't heard of this manga until a friend introduced me recently. Unfortunately, I didn't really connect with the material. This isn't a slight against the art, but rather that most of the vignettes just didn't land with me.
Unlike long-form manga, What's Michael? is set up more like an American newspaper comic strip, with the stories told over just a few pages. There's not much in the way of continuity -- and that's sort of the point. What's Michael? is meant to poke fun at how humans interact with cats while imagining the secret lives of our feline friends.
Cat owners (like myself) will no doubt get a chuckle out of certain anecdotes, but many of the gags came off as either nonsensical or just not that funny. Often, the vignettes went nowhere.
On the other hand, Kobayashi's art style is a wonderful snapshot of 80s manga, and I'll add my voice to others who have noted that he has a fantastic grasp of cat body language.
What's Michael? was diverting enough for the short time it took me to read it, but I likely won't seek out any further volumes. However, it would probably be great for young readers or folks just getting into the manga medium.