I have one story that has two MCs and occasionally switches POV to side characters when needed. I love the scope and depth that multiple POVs can give, and I don't know if you can have too many (Well...yes, you can. A book with over 30 POVs would be hard to get through.), if you do it well.
As for recommending books for multiple POVs...LOTR, for one thing. And also there's Auralia's Colors and the rest of the books that switched POVs quite frequently, at least the ones I have read do.
I also have a book I can point you to on how
not to do it.

I literally put the book down and wouldn't finish it because this was done poorly. In this book (which I won't mention by name at this point), there are over 7 POV characters. Which is fine. Except the authors did not give that much thought as to how to go about handling the POV changes. I couldn't keep track of the characters and their settings, their names, their personalities, sub plots, and I was never able to relate to any of them. In one instance they introduced us to a character in one chapter and left it on a cliffhanger, but not get back to it after eight or nine chapters of more disjointed confusion, until I had almost completely forgotten about the character and the cliffhanger.
There were other reasons as to why I didn't like this book, but that was the major reason I put it down.
So when shifting POVs, make sure that you put a lot of thought into how you handle the characters. Make sure the reader has a chance to get to know the character, and don't go too long without covering the character again.
Ultimately, multiple POVs can be very powerful and effective, and each POV adds another layer of depth in the story. But it does have to be used carefully.
