It's not that bad. As said before, T4
(Iberia/Oneworld mostly) is a little longer, as the buiding is huge and depending where your plane is docked it can be quite a long walk to the middle of the building, where immigration is located.
The next step is taking an underground automated train which takes approx 5 minutes, and then a short walk throught luguage claim. It's not as bad as it sound but count between 15 and 30 minutes depending where your plane is docked.
Exception for non Schengen flights in Europe (i.e. London) which do NOT dock at the remote terminal 4S (Satelitte), Then you will be out faster. That's for T4
For all other airlines it's fairly straightforward (T1/2/3) and not worse than in other airports. However once landside it's sometimes quite a hike to the car park or metro depending on which terminal you arrive.