For starters, I like first person. Yes, there are readers who claim “I won’t read ‘I’ books.” I know one agent who will not rep first person books, period. First person limits the writer because everything is seen through one pair of eyes. Backstory, plot, characters all await to be revealed – to the Main Character and the Reader alike. To me, this is a good thing, for it allows the MC and the Reader to travel together on a journey of discovery.
The key to first person is the voice. If the Writer’s voice is compelling the Reader will be interested. A dull voice will not carry any story, but first person is acutely vulnerable to voice.
Third person frees the Writer from a single POV. Jumping from one character’s head to another can be a joy, if it’s done right. Here are a few tips from Sleuthfest to help keep you on track. First, when changing POV, Meg Gardiner offered this advice. “Don’t spend too much time away from the MC.” If you spend too much time with other characters, the Reader gets drawn away from the MC, and this may negatively impact the Reader’s experience.
Another third person trap is omniscient POV. The story shouldn’t be told as from a camera lens observing the action, but from inside the head of the scene's primary character. Changing POV allows the Writer to provide information to the Reader from different perspectives. But the Writer must take care to let the Reader know which character is commanding the scene. Chapter breaks or a few lines of white space can help the Reader know there is a shift in POV.
One way for a Writer to choose a writing technique is to read - a lot. Which method draws you in? Try the style for yourself. How does it work for you? How will it work for your Readers. One of the best pieces of advice I heard was from Dennis Lehane. "Write the book you would like to read."