I didn't come across any first person writing until recently, so it always takes me a couple of pages to get used to that POV. I default to third person, but I have done a couple of short stories in first person that were fun to write. I may explore using first person for longer pieces some day.
I've heard that the use of first person grew in popularity with the rise of young adult books. I don't know if this is true or not, but most of the YA books I've come across are written in first person. I think the argument was that many young adult and new adult books are about characters who are still finding their footing in life and as adults, so using first person helps make that experience more visceral for the reader.