There's a Fantastic Four set coming out as well, I think either this month or next month. I have the Spider-Man one. The scanning is pretty well done. It's all in PDF. Obviously the oldest issues are not as crisp because they're scanned from someone's collection (the set says who but I don't recall)... newest stuff is of course great-looking. I imagine the FF set will be very similar.
Needful Things actually came out around 1991, actually, and to say that that was his last good book is not true. Since then he has finished the Dark Tower series, written the amazing Insomnia, Black House, and Bag of Bones to name a few.