Personally, I think that the 'limitations' to first person are just an excuse people use when they don't want to put forth the extra effort involved, or can't write in such a challenging style. It's possible to write in first person and have an unreliable narrator. Your character just has to be highly opinionated or not have all the facts. And even though it can add serious length to a book, you can simply choose to do first person with multiple characters' view points so you aren't 'stuck' in a single perspective. You can show whatever you want to show as long as you are willing to head jump and can pull it off effectively. And personally, I find that the most entertaining books to read are the ones that allow me to do my own thinking. As a reader, I don't need a guide to tell me what to think. And as a writer, I can use my characters thoughts and actions to show people what I'm trying to say.
I agree with Marturion. Writing in first person is extremely challenging and extremely rewarding. I love the intimacy you can get with first person, and I believe my current project would seriously suffer from a change to third person. The change might make it easier to write, but writing isn't supposed to be easy.
I chose to write my current project in first person because I wanted to show on a very intimate level what it's like to live with epilepsy. I will always consider writing a new project in first person. It makes writing more entertaining for me, it improves the quality of my writing (because I can get in touch with my characters more easily), and it helps me grow as a writer, which is my top priority right now.