strange... i never ever used styles while using word - and editing larger documents was painful. then it seemed to be a normal practice. only after using oo.org i learned about styles - and i am continously amazed that word has no concept of page styles. i've seen a lot of documents that people send me with questions "why the hell it behaves like it does ?" - andi can easily see what has been formatted with which style and send them back corrected document.
i can agree that using styles can be more time consuming in short and/or simple documents - but for longer documents this might be true for word (last time i tried to do that just to see what it's like, i just dropped that idea). for anything longer than a couple of pages styles will help you a _lot_. and writer handles them pretty well in my opinion. charts might have more detailed styles, there are some minor things that i would like to change in calc's handling of styles, but i use writer's styles every day and i could not do without them anymore.