The thing about this book and why it's taking longer to write than the last 3 is due to its style change. Where most writers (at least those that I've spoken to) find it difficult to write from a first person perspective, I do not. I enjoy it quite a bit. It's more psychological, less flashy, more to the point and if done correctly, it'll give the reader a much better understandig of the character(s). After all, you're seeing it through their eyes.
For me, third person narrative seems to be harder to do. It requires a heavier dosage of metaphor, anaology, etc... to be enjoyable, but not so heavy as to come out poetic. That's not an easy line to find and from what I gather, it changes with the audience, the writer and even the story.
Oddly enough, I'm finding this more challenging than flipping perspectives during a fight scene (something I did in book 2 and a little in 3). I think it might be that I don't generally write in this fashion and I'm probably being more critical of myself than I should be. Honestly, it feels a lot like writing my first book all over again. The best comparison I can give you would be starting a new job (one you actually want). Those first few days you don't want to mess up, you double/triple check everything you're doing....it's stressful. That's how this feels. I think once I get some beta readers to check it out and get some feedback I'll calm back down and not worry about it so much. Until then, the going is a little slow. On the bright side, at least you know I care and don't think everything I do is gold!