Having enjoyed book one and largely not enjoyed book two, I read this more out of a sense of duty to finish the trilogy than anything else. That said, it did go some way in redeeming my overall view of the trilogy... these are not books I'll be re-reading or recommending to anyone else though. Overall they were ok, but not good enough to be worth the time they took to read, and more importantly, not worth the other books I could have read in that time!
The hero of ages did a lot of dramatic revealing and plot-twisting, which was enjoyable. The sense, as the end approached, that Sanderson was completely unravelling the world he had built, was exciting and kept you guessing about what might break next!
The Kandra were a fantastic invention, and I would probably have enjoyed their role in the story to be drawn out more, while compressing the ever frustrating vin-elend storyline.
Their marriage, if anything, made them more annoying and even began to corrupt Sazed, which was a shame. In general, as with the other books, the story is good but the characters are not; the dialogue, both internal and external, is clunky. I really didn't care what happened to any of them, so long as it meant they would stop whinging about their feelings.
The gradual understanding of the psyche of the lord ruler was good way to break the obvious good and evil battle it seemed it would be at the beginning, but the hero of ages mystery was drawn out over so long (is she the hero? Is he the hero? is no one there hero?), that again, I couldn't be bothered to be led by and of the 'oh, so SHE's the hero' twists he kept putting in, because you know there will be 10 more before the conclusion. I'm also not sure whether the ending was an interesting twist, or just a slightly lazy way of avoiding resolving the chaos he had got his world into.