I've been a long time Quark user, I think I switched when I got fed up with Pagemaker 2.0 a zillion years ago. I've been resisting InDesign, but with the advent of formats like PDF, we've been freed (for the most part) of having to be locked into Quark because of vendor requirements.
So now I'm thinking about moving to InDesign as my main pagelayout app.
What do YOU think?