The Hero of Ages: Book Three of Mistborn by Brandon Sanderson (4.5 stars)

Great book, it reached "don't want to put it down" levels at the end. I really appreciate that Sanderson tied things up in 3 reasonably-sized novels and wrote a real ending. Mad props, that's very difficult to do for these huge world-building efforts. 

Heading to downtown spoiler town.

Very impressive pacing: I think he held onto the specifics of hemalurgy and the importance of spikes for quite a long time, as well as several other key points. We've known about Inquisitors and spikes through the eyes from book one, but it isn't explained until 2/3 of the way through book three. 

Also, impressive that he drops some hints about the earring to give readers a chance to exist in a "NOOOO, don't put it back in your ear" state before it's spelled out explicitly and Vin twigs. 

There's a few obvious interesting side stories that could use their own treatment: Marsh, Human, maybe the Kandra first generation. 

This series is perfect for TV series adaptation, I hope someone makes it.

Some things that bothered me: 

• Elend gains spectacular powers that equalize his footing with Vin. I really wished he had to continue to operate as king from a position where his wife had significantly more magical power. I don't think it was at all necessary to re-balance into a state of patriachal power. Almost all of the significant characters apart from Vin are men, including all the kings :( 
• Sazed gets really mopey, which is probably realistic, but was pretty annoying to read. 
• Canned food in the storage bunkers doesn't seem to match the technology level of everything else. 
• No-one figured out how to turn steel pushes into electrical power, or at least industrial applications. It was just the nobility faffing around using it to fight each other by throwing coins around. The first house that figured out how to make an Allomancy-powered mill/forge/train/carriage/whatever could have dominated global trade. I'm told this happens in later Sanderson books.
• The ending was pretty good, but I didn't buy that all that was needed was some tidbits from Sazed's stored books to fully correct all the previous mistakes. I'd say it's more likely that the star measurements in those old books were wrong than right, and they certainly wouldn't have been good enough to put the earth back into the exact correct orbit. Even assuming infinite understanding afforded through the magic it seems like the most likely outcome would be to break the world in a new way. I think the best possible ending would be one where some stuff got a bit better but the world was still massively broken, and maybe broken in some new less-obvious ways. The actual ending felt a little too happy.

Things that were great:

• Spikes, and the significant role they play, but I feel like he shied away from the full gory reality of what was going on with the inquisitors and koloss. Earring was clever.
• Ruin is just cool. So are the Kandra.
• The atium secret was a good reveal, I didn't pick that one. Combined with the secret of the mist sickness was genius.

4.5 stars.