UPDATE TIME:

So I basically had 3 problems:
- material wouldn't stick to the build plate;
- PLA would warp;
- I had(/have) no idea what the flip I'm doing.

Step one:
I got the BuildTak mats to cover my (bend) Aluminum heated bed. Started printing ABS. The amount of stick was amazing, So I did some test prints first:



With only 2 shells you can see some open areas at the top where there was no material to print onto, and there are some visible 'dots' on the bottom half; probably due to the relatively large overhang.

Then I printed Marvin again:


For some reason his 'eyebrow' got burned a bit.. and the overhang isn't perfect.. but I can clean that up if I want to, so the overall result is great! (Especially compared to it's older PLA brother that was my first print when I just got the printer.)
(can't add more images, so I'll continue in next post)