I have to say that the results surprised me quite a bit.
I tested the absolute absorbency of the Abena X-Plus and the Bambino Bianco by first weighing them dry and then weighing them after soaking them in water for 10 minutes, then letting them hang to dry for 10 minutes. I also did the same thing for the Abri-Let Maxi and the Bambino Quadro. I used a kitchen scale that measures to the closest 5g; not that it really mattered in the end, there was one very clear winner...
Abena X-Plus - 185g
Bambino - 165g
Abri-Let Maxi - 70g
Bambino Quadro - 45g
Abena X-Plus - 4255g
Bambino Bianco - ~6600g !! It actually exceeded the kitchen scale's range so I weighed it on my bathroom scale (14lbs.) and converted the result.
Abri-Let Maxi - 620g - this had a lot of press out/runoff when I hung it up because it is mostly pulp. It also compressed in thickness as well.
Bambino Quadro - 1880g !! This one swelled to almost quadruple the thickeness of the Abri-Let !! I will post a picture to my gallery of the comparison. It is impressive considering the dry comparison pictures.
Wet Bambino Quadro and Abri-let Maxi Picture
Needless to say the Bambino products have, by far, the greater absolute absorbancy (and much better press out characteristics).
The only thing is that, I've never come close to reaching the capacity of Bambinos; whereas, I always seem close to maxing out the Abenas. The Bambinos always leak well before full capacity for me. I seem to get more wear time out of the Abenas.