Although I've only read about five stories from this edition (so far), I've read most of the Conan stories before in various collections over the years. I already know that it's going to get five stars because most of the stories are great. Those that aren't are still good and are not going to detract from overall high standard of this collection.
This collection contains all the Conan stories written by Robert E Howard in the order they were published including those published posthumously and unfinished drafts and fragments. The stories are in their original form, unedited and unfinished by Sprague De Camp and Lin Carter which is one of the reasons I wanted this collection. It also contains some nice illustraions.
Ultimately this is something you buy if you already know you love Conan and just want the ultimate collection. If you haven't read any before and are looking to try, I would suggest something like this: Conan the Warrior
which contains three good quality stories.