I took in two males for my neighbor a few weeks ago, and they were so pretty and seemed very bonded, I thought it would work. They did pretty well when I was able to let them fly outside their cage, would even share a nest at night snuggled together. After a few days where I couldn't do that, though, they started to attack each other horribly! I thought it because of the nest, so I took it out. Still one totally dominated the other and in the evening when they wanted to roost, he started pulling out huge tufts of feathers and beating up his cage mate so that he had to sleep on the floor. If he moved during the night, I'd hear the other come down and beat on him further.

I took them to the pet store today, where they were put in with about twenty other zebras in a big flight. I feel sad, because they were so pretty, but I just couldn't deal with them. From my experience zebras do well in an aviary. I don't know how anyone is able to keep them in a cage without them killing each other and especially how they can be kept with any other species. Maybe other people's birds aren't as violent as most of mine have been...
For me, societies are the perfect finch. They may be plain, but they are gentle and calm. I don't think I will be tempted again by any little orange cheeks and red beaks any time soon.