I just finished reading an advance reader's copy of Hero of Ages, and can't say enough about how good it was. Apart from one desultory chapter in the early going, Sanderson's book is a page-turner that'll blow you away with revelations that you will not have seen coming. Sanderson connects all the dots by the end, and leaves nothing unanswered. It was a pleasure to read a trilogy that in no way is going to keep going.
At least I hope it doesn't keep going. The ending was terrific, and one more chapter would have ruined the series.