Dual shock 4 is the best controller

Wii-U pro controller>Xbox One controller>DS4>Gamepad.

Pros for all.

The pro controller gets 70 fucking HOURS on a single charge. The Xbox One controller has the best analog sticks. The DS4 has the best d-pad and the gamepad has the touchscreen.

Cons for all.

The pro controller has weak rumble. The Xbox One controller' d-pad is lacking. The DS4 controller has horrific battery life and the gamepad is just too damn big.

The WiiU gamepad is uncomfortable as hell and has a realy cheap feel to it. So that's dead last in my list. Though if games could use it more interactively and less as a peripheral it would be in the conversation.
Since I have small hands I always favored DS controllers over XB ones so I'm a bit biased but DS4 is rechargable, has a front touchpad, a headphone jack, a monophonic speaker and a rear color bar. These controllers do retail at the same price in my country but buying an official rechargable battery pack costs an extra 25euros (though you can find unofficial ones as low as 10euros).
To wrap up I feel the DS4 is the best controller for me mainly because it feels more comfortable in my hand and it offers new unique ways to interact with games.

Why buy a charge kit when you can just buy 4 rechargable AA batteries? 

Cant decide if people that go "gamepad" are trolling or not...
I think some of them are, others actually love the feel of that controller.

Wii U gamepad = about 500 grams (half a kilo)
DualShock 4 = about 200 grams (1/5th a kilo)

Also one of these two has ergonomics in mind, when they where designed... and it wasnt the gamepad.
But I guess the 2nd screen trumps the other things, the gamepad might be behinde with?

I use the Wii-U pro whenever I can get away with it, not a fan of the gamepad.

Dualshock 4.

DS4 easily. XB1's lack of reacharable batteries alone makes it lose against the DS4. the WiiU's controller is just huge and clunky, and it didnt give us "new ways to play" like it was promised.

Wii U Pro Controller > DS4 > XBO > Gamepad.

Pro controller is ergonomic, has the best analog placement, great battery life, and digital triggers, which is a bonus to me because they're responsive.

I use rechargable standard AA's for my One. As for 360. 2500 mAh.

1. Xbox One Controller. Still great ergonomically, really improved d-pad, trigger rumble is nice, 25-35h with AA rechargables.

2. Wii U Pro Controller. If that thing had analog triggers and concave thumbsticks it might actually be number one. And it runs 50-80h with a charge.

3. Dual Shock 4. Ergonomically greatly improved. Touchpad is a nice idea. Personally i don't like the stick position. Actual downsides though are the really short playing time with battery and i know to many people with quality issues already.

4. Gamepad. Nice ideas badly used. Trigger and bumper position sucks. Sticks are to close to buttons/d-pad, the actual basic form factor is bad as well. Ergonomically it's just crap. Then there's the short running time for the battery. Except for asymmetric gameplay and off-tv you could do anything the Gamepad can with a standard controller with gyro and touchpad.
If i'm not playing one of the two, three games that really make well use of it, the Gamepad is only for off-TV.

The first three are actually close together in my opinion.

1) Wii U
2) XBO
3) PS4