Geeetech prusa i3 pro B quality issues

[mjf55]

Hello,
I have a prusa i3 pro b from geeetech. I have some quality problems with it. You can have a look on the below pictures and let me know what do you think it is the problem:
https://www.dropbox.com/s/hewpedzapw..._3723.jpg?dl=0
https://www.dropbox.com/s/2srwazvspd..._3724.jpg?dl=0
https://www.dropbox.com/s/k90njujdxl..._3725.jpg?dl=0

I know that nozzles temperature does not fluctuate for more than 2 degrees Celcius. The Z axis are also calibrated. The filament that I currently use is Esun PLA but the issue occurs with almost any filament.

So, some basic questions.
What extruder and bed temperature are you printing at?
What is your part cooling fan set to, and on what layers?
You say you calibrated your z-axis, how? what height did you rest to?
Any other model print this way?
Did you calibrate your extruder ( i.e. make sure when you tell it to extrude 10mm, it extrudes 10mm )?