I'm always in favor of individual character accounts since I like things nice and neat. I understand the simplicity of having one OOC account for plotting and posting in shippers but as a typically 1 or 2 character type of person, my vote would be for individual accounts.
I do tend to prefer a regular application though. I like having the app double as the shipper since it saves me a lot of time, but I also like to lay out some detailed backstory, and the shipper app isn't really the best place for that.
This is all personal preference though. I can work with whatever.