Just beat the game. Took me 11 hours on Hard.
I'd rank the series as follows: Among Thieves > Drake's Deceptions > Drake's Fortune
Compared to Among Thieves, here's what it does better/worse:
+ More memorable soundtrack
+ More engaging puzzles
+ Greater visual fidelity (some of the set pieces late in the game have to be seen to believe)
- Worse combat and enemy encounters
- Worse plot
- Worse pacing (takes a while to get good)
- Less developed characters
- Overdone and wonky animations for Drake
- Stealth is not nearly as effective
- Dialogue is less witty
- Cutscenes are less interesting
- Ending is not as satisfying (including boss, thanks to the less developed characters)
Ultimately, the game felt far more rushed than the previous entries. It takes a while to really get going (not until chapter 12, really), and once it does it's still marred by some jarring inconsistencies. The pacing is a huge issue, but this is almost entirely due to the combat scenarios. Even with the aiming patched, the game's enemy encounters are just not fun compared to Among Thieves, period. The arenas are set up closer to Drake's Fortune, which is not a good thing. The enemy AI is perhaps the worst I've encountered in a game of this size and budget, which makes no sense considering how satisfactory it was in the previous entries. Enemies literally scurry around the map like mindless rats, making it hard to hit them and keep track of them. Plus, every encounter is virtually identical: couple snipers, an RPG, dudes in armored suits who are annoying to take out, and a plethora of grunts running around aimlessly.
The puzzles are satisfying for the most part, but they cease to exist from Chapter 12 and onward for whatever reason and are instead replaced by near consistent combat encounters in the last few chapters. Very annoying considering the combat is not fun at all in this game. It's impossible to even stealth your way through it, which is contrary to Among Thieves, a game that allowed you to stealth entire areas even on Crushing.
Anyway, there are a lot of small quibbles in the game that add up, like Drake's animations (making jumping into and out of cover more frustrating than it needs to be), the fact that the villains and supporting characters are barely explored, the fact that the story and plot is all over the place, etc., but ultimately it IS an Uncharted game, so it's automatically more engaging than most other games out there. The set pieces once again are truly incredible, there is some amazing artistic direction here, the soundtrack is one of the best all year, and when the game works, it's sublime. Unfortunately, this one could have used some more time in the oven.
Final rating: 8.5 or 9 out of 10, not sure.