Q:

Best puzzles of 2017 Q4 (October - December)?

This question is part of the best-puzzle award series.

What are your nominations for the best puzzles, here on Puzzling.SE, of the fourth quarter (October/ November / December 2017?

Suggested guidelines for nomination:

Nominate each individual puzzle in a separate answer, so they can be upvoted/downvoted separately.
No more than 3 nominations per person.
Don't nominate your own puzzles.
Before you nominate a puzzle, check to see if someone else has already nominated it. If they have, then add to that nomination as a comment (or edit it) instead of nominating the same puzzle again.
In your nomination, explain what it is that (in your opinion) makes the nominated puzzle such a good one.

Some lists to help jog your memory (your nomination doesn't have to be from these lists):

Algorithmically selected "best of":
  
  
Popular puzzles, both in score and in vote to view ratio, from 2017 Q4
Well received puzzles you may have missed from 2017 Q4

Best by votes/views:
  
  
Questions with the most votes from 2017 Q4
Questions with the most views from 2017 Q4
Questions with the highest-voted answers from 2017 Q4

Meta-meta issues:

Is this kind of thing allowed on SE?

Yes, Photography SE and Sci-fi/Fantasy SE do something very similar. 

What's the point?  

To highlight and encourage good practice in a way that goes beyond upvotes.
To work towards building a 'hall of fame' of some of the best puzzles on the site (perhaps to reside on a future puzzling.SE blog) - think of it as our 'greatest hits album'.
To prompt members to put forward their own reflections on what makes a high-quality puzzle.

A:

Japanese Fusion Alphabet Soup by Alconja
Obviously, it's a huge repository of good quality cryptic clues, which is always nice. Other than that, this puzzle doesn't look very impressive at a first glance, which to me is the most impressive thing about it. This might not make sense, until you realize the many layers of the puzzle required the crossword to be constrained in at least four different ways, with the constraint in the middle section being already really impressive in and of itself, and Alconja made it look completely effortless! I had a lot of fun working on this one, even if Deusovi got to the final answer first.

A:

You've got an 11.111111% chance to solve this! by Mister B
This puzzle looked terrible at first! In fact, one of the first comments was a link to the "What not to do" post about ciphers, and user Bass did a lot of steps to analyze it. But in the end we got to watch as, step by step, the answer was found, and everyone agreed that it was actually a solid puzzle.
And the creator, Mister B, clearly put a lot of work into making it, including such things as:

 Creating the plaintext such that, after a Vigenere cipher, an acrostice appeared in the ciphertext

and

 Fairly using Morse Code, Skip-Counting, Vigenere, and Rot25 in the same puzzle with subtle clues rather than hoping someone would guess a step - every piece of the decoding was clued somehow.

This was more than just a cipher or set of clues, like many "puzzles" we see here. This was, from start to finish, a true "Puzzle" in purest form.

