Having read them all, I'd rate The Steel Throne in the Top 3, along with The Crane, and The Dragon, in no particular order.
While the previous 7 books in the series deal with the doings of one main character within a short timespan (a few months, at most), this one spans the decades long conflict known The War Against Spirits and there is no main character. Instead, each chapter centers on one character, then jumps forward one month, or several years, to the next. This, far from being confusing, makes for an entertaining and dynamic read.
When dealing with game-based fiction, or shared-world fiction in general, one must thread carefully the narrow line between fulfilling reader expectations and crafting a compelling read, with a few surprises to boot. In my opinion, Mr. Bolme has succeded. Most bases are covered, questions long raised are finally answered, and a plot and characters only hinted at in one-liners on a piece of cardboard are made alive in this most satysfing novel.