I agree with elwynor. Ability to add a user to multiple groups is critical. I was so happy playing with the trial version of the software because it was logical and took care of what I needed as far as ACL is concerned, until I learned of the multiple group access limitation.

Consider the following scenario. I am creating a school portal. Students are divided by grades. Parents get access to information posted for the grade that their child is in, rest of the information is hidden. If the parent has more than one child at the school (which is very common) my access levels fall apart. The parent would have to have two separate logins to see their kids' info (people will not like that). The only way around it now is to create combined ACLs. The problem is that there are quite a few combinations of those possible: kindergarten and grade 3, grade 2 and grade 5, and so on. Makes things very complicated.

thank you for your clear explanation.

I probably will eventually integrate such functionality, but there is still the whole move to the mvc model first, so do not wait for this to happen.