Personally, I find it's a lot easier to write in first person vs. third person. However, with that said, many agents/publishers consider first person point of view to be amateurish, ostensibly creating a rather nasty barrier between writers who prefer this technique and their odds of achieving publication. This pickiness is one of the many, many reasons why publication through mediums such as Kindle and Nook are becoming so popular.
First person point of view, in my opinion, takes the readers along for the ride more effectively than third person. Afterall, aren't first person shooter games a hell of a lot more interesting than first? In first person, you tend to relate to the protagonist more and the story flows more fluidly (both for the reader and the author). What's the down side to writing in this format? The plot. If you have a rather complex and involved plot or subplots, writing in first person is very restrictive to how far you're able to explore those plots as the protagonist has to essentially be involved in almost every aspect of each one. This is where third person works more efficiently. Third person doesn't limit you to one character or one setting at one time which is why you will see third person used more in adult literature.
In my novels, Enigma Black and Vendetta Nation, I found that I wanted to focus on characterization as well as involved subplots. Thus, I opted to go with both points of view (which is widely frowned uponm, I've never been one for the conventional). Albeit, I use the third person points of view sparingly with its presence appearing in very limited chapters. I also do a clear section break as to avoid confusing the reader. This is incredibly important if you're going to blend these two writing styles successfully.
Initially, I began writing Enigma Black (the first novel in the series) in third person. It wasn't until the third chapter that I realized this technique just wasn't going to work and decided to give the finger to "conventional" by adopting my own "no rules" philosophy. In my opinion, it's worked out great for me (others may and probably do disagree) and I have a massive amount of respect for those authors who can blend the two styles harmoniously.
With my two cents out of the way, I present to you first vs. third person point of view. Lets get it on!
-Done from a single character's point of view (POV for us cool people) throughout the book, it gives the reader a biased opinion of the other characters through the protagonist's eyes.
-We as the reader know exactly what's on the protagonist's mind (except, if you're Edward Cullen and the protagonist is Bella, then you're just f***ed).
-Usage of the word "I": "I wasn't sure what I was going to do"; "I thought"; "I wanted to go bury my head in a hole after reading...".
-More women write in first person than men (I actually think I have yet to read a first person written by a man).
-First person is character oriented (men seem to be more plot/action/suspense oriented which may be a reason why they shy away from first).
Advantages of First Person
-The writing flows easier. It's good for beginners.
-Good for the insertion of humor
Disadvantages of First Person
-If you aren't spot-on with characterization it will be blatantly obvious.
-Subplots will be difficult to formulate and maintain making it difficult for a series character to carry a plot-oriented storline.
-Your story can very easily become monotonous.
-Compared to third person books, there are not that many first person books in publication.
-Mainly seen in YA
-Can be done from one character's POV or many character's POV.
-The POV character is referred to by their name or he/she: "Roger wasn't sure what was up with Sally"; "Men," Sally muttered in disgust. It was clear to her that he just didn't get it.
Advantages of Third Person
-Complex storylines with multiple subplots.
-Suspense can be built by switching POVs.
-Publishers are more interested in third person POVs.
Disadvantages of Third Person
-It's easier to confuse the reader by hopping into several character's "heads" at once.
-Lack of character development.
-By repeatedly switching scenes and POVs, it's easier to alienate the reader from the characters and the storyline.
The bottom line is a writer should write what they want to write and in whatever style they feel comfortable writing in. Should an author venture away from their comfort zone and test the waters once in a while? Yes, of course they should. But if you find that doesn't work for you, then write what does. Never compromise yourself and your style for the wishes and desires of others. Trends are fickle and so is the literary world. One day your style could be discouraged; the very next day, it could be encouraged.