I used Quark for many years, for book and magazine work. Loved the program but the company was terrible to deal with.
The loss of Quark is a sad thing mainly because Adobe has no serious competitors today. You only have ID now because Quark had set the bar so high that Pagemaker couldn't compete. And Illustrator was much better because it had to compete with Freehand. The period where both drawing programs were fierce competitors was a wonder to behold, with each one getting better and more capable with every update.
Now, without a serious challenger, the Adobe products get buggier and more bloated with each new update. Illustrator is downright terrible in some respects. (Why does "snap to" only work intermittently; and why does it snap inaccurately at other times?) And the whole "Creative Suite" is really just a marketing fiction. They're up to CS6 now and there is still nothing like a truly common interface. Doing the same task in each program often requires a completely different strategy.
I don't feel sorry for Quark. They got what they deserved. But I do lament what a lack of competition has done to Adobe -- and those who have to use their products.
Mark
P.S.: Ventura publisher, running under the old GEM GUI was a wonderfully capable program.