I enjoyed the final of Gemmell's work (Troy:Fall of Kings) which was finished by his wife. Although it appears that he had enabled this to be done more easily (and implicit permission) by preparing chapter plans when his heart surgery was looming - as per
http://entertainment.timesonline.co....cle2320620.ece (if it is to be believed).
I also must admit I did not object to the final two books based off the plans to "Dune 7"
I suppose I liked the idea of having an authors "intent" finished, it's about the content the characters and the story evolving, I suppose in both of the above cases I wanted to know what happened next so was glad they were released. In both cases the author had died with plans to continue their works, and in the case with Gemmell, in such a way that I think leaves no interpretation that his intention was for somoene to finish the work.
(I am sure that you will find people who are just against such things as I am for them, but each can vote with their money dollars!)