Personally I find it more helpful to completely write the story, but break it up into sections that can be uploaded piece by piece later. That way I'm able to update fairly regularly, only having to proof read, and the story is fairly easy give minor changes to as the reviewers comments. This way also you get to keep your eye on the completed story and know what changes NOT to make (Sometimes there's a reason for a character to be acting OC, or for a setting not to get a thorough description until later). Let's be quite frank, feedback and suggestions are nice, but this is your story and you shouldn't be overly eager to change its more integral parts. I like to look at the first completion as more of a rough draft, along with the first chapter unless you happen to have a beta reader. Its got the whole plot down and most of what you want to say, and it can easily be changed based on suggestions.
More importantly, I think, is the fact that this method helps to make writer's block more private and easier to deal with. One of the worst things I've seen is some reviewers getting absolutely harsh with a writer just because the story has stagnated. It really aggravates the situation and sometimes causes the writer to lose complete interest in the tale, leaving both sides completely unsatisfied.
Of course chapter installments also have other advantages. People tend to get very scared by large amounts of text, anything over fifteen pages can be very daunting to read, no matter how well written. Some of the most popular stories are well over ten chapters but each chapter is only about ten pages long so readers nearly always make it to the end of a chapter to leave a review.
Well that's about all i can say on the subject for now. I look forward to seeing your story.
Proud Fan of Sonic Underground.
"The evil that men do is nothing compared to the evil that we do."
- G'Narl; Overlord.