POV: First or third person? Or, both!

I write in third person. For me it's just easier, gives me the way to hint at what the other character is thinking by describing their reactions from the main characters POV.
I have tried writing in first person, and it just doesn't sit with me.

My friend Nicole, has written her book the Arrival in an interesting mix of first person and third person. She has had many comments on how confusing it is, so you shouldn't do it.
Here is an article about how to do it, and that you can do it.

Nicole's way is not to change POV per scene but rather most of the characters have their POV in the same scene to give the reader and interesting and new way of broadening each scene.
I will admit that at first it was a tad confusing. I had told her the same, not to do it! But she was firm in her choice and i applaud her for that. I am by no means a professional, and after a few chapters it actually all came together.
That and the interesting story!

What do you think of switching from third person to first person in a single work?
If you've read Nicole's book, The Arrival (It's free on Amazon, so there's no excuse!) how did you take her interesting style?
What is your POV preference - both writing and reading!