making responses for an NPC using the 'conversation editor' and by making a quest, going to the 'topics' tab and making responses?

Or is there no difference at all?

Which is the better way to make dialogue?

Thanks for any help, I appreciate it a lot.

Oh and sorry for my many topics, its just that I am making my mod now and I really have lots of questions / problems. =/

There is no real difference. I have found that the conversation editor renumbers topics, and its topic names are really long. So if you start with manually named topics in the topics tab, you may not want to "fine tune" with the conversation editor. It does not break anything, but if you have written notes with topic numbers, they will not match the result of the conversation editor anymore.