http://www.gamesindustry.biz/articles/2012-04-02-wii-u-less-powerful-than-ps3-xbox-360-developers-say

"No, it's not up to the same level as the PS3 or the 360," said one developer who's been working with the Wii U. What does that mean? "The graphics are just not as powerful," reiterated the source.

Anonymous developer

Funny thing is neogaf confirmed that wiiu actually has less shaders

"This developer is not alone in their opinion. Another developer at a major company confirmed this point of view. "Yeah, that's true. It doesn't produce graphics as well as the PS3 or the 360," said the source. "There aren't as many shaders, it's not as capable. Sure, some things are better, mostly as a result of it being a more modern design. But overall the Wii U just can't quite keep up."

http://www.eurogamer.net/articles/2012-03-26-darksiders-2-dev-wii-u-hardware-on-par-with-current-gen

"So far the hardware's been on par with what we have with the current generations. Based on what I understand, the resolution and textures and polycounts and all that stuff, we're not going to being doing anything to up-rez the game, but we'll take advantage of the controller for sure."

http://www.nintendolife.com/news/2013/09/developer_interview_black_forest_games_on_bringing_giana_sisters_twisted_dreams_to_wii_u

""Overall the hardware itself is slightly faster than the other current-gen consoles. 

"Then we started working on the port, we already had our game released on the X360, and going from a console release to Wii U is easier since the consoles have very similar performance characteristics"

http://mynintendonews.com/2013/05/17/ea-senior-engineer-the-wii-u-is-crap-less-powerful-than-an-xbox-360/

EA SENIOR ENGINEER: ‘THE WII U IS CRAP, LESS POWERFUL THAN AN XBOX 360′

The EA senior engineer was nothing more than a troll.. He was  simply  spewing nonsense....

maybe but why would he lie about something like this if there wasn't any truth to it. saying wiiu is less powerful then 360 he knows the the real specs of both consoles for sure, so i doubt he would say something like that if the wiiu had way more shaders, which it doesn't.

OK, so this thread isn't going to go well, but I'll give my 2 cents.

Reasonable people know that the WiiU is weaker than the PS4/X1. It has some nice features that give it some minor benefits but it is weaker in most ways that count for devs and third-parties are going to struggle to get multi-platform games working well and looking good in a timely manner.

It should theoretically be more capable than PS3/360 (doing more with less raw power), but until we have tech heavy games specifically built from the ground up for WiiU, no one is going to be convinced no matter which side of the fence they sit on. Monolith Soft's X will probably be the main one.

Power is more than a number.

When I say
PS360=1
Wii U=2
XBONE=6
PS4=10

Those are just general "power feels." Really general. Another dev depending on how they code and work could have radically different power feels. If you learned to master the 360 for example, the wii u could feel really week in comparison until its tips and tricks are discovered.

Xbox 360/ PS3

WiiU

XONE

PS4

I think the difference in opinion comes from two major differences with the developers.
The developers that say the Wii U has trouble keeping up are the ones who are used to working on PS360 and using their faster cpu's & memory bandwidth to produce large AAA games with sophisticated AI and interactions. These developers then look at the Wii U & start scratching their heads because there doesn't seem to be enough water to fill the bucket.
The Developers who say the Wii U is moocho powerful are mostly small/indie devs who traditionally never used the full PS360 cpu power for ai or complex interactions, but rather used it to try make their rather simple games look pretty. With the Wii U these devs used the extra gpu power to achieve good results because they never relied on fast CPU's in the first place to make their games run.

I don't really understand the title...

"Why do we keep here different account stories about Wii u hardware power."

do you mean, Why do we keep hearing different stories about wiiU's hardware power?

And based on what you quoted, the all seem pretty much the same...

The accounts aren't different at all, people just want to hype either the positive or negative aspect to suit their agendas. We need X, Bayonetta 2 and Project CARS to be released so that this entire debate can end once and for all. I already know where I stand but hopefully those 3 games will finally make people see the light. No more excuses after that from anyone.

lol, except SS3 Goku couldn't beat fat Majin Buu.