-What were your general thoughts of your experience in dealing with them as allies and foes?
I was usually a loner type as far as Nexus went in the beginning, and really towards the end. You get powers that help you out if you don't want to be part of a perma gank, but the bond is pretty nice in general. In dealing with them as allies with the bond they can either be really great, or bring you down really fast. It's good to have two competant people together that can play on each others strengths and just really dominate.
As far as foes go, once I was ranking with 2 Nexuns as a goodie, had the balance shift while we were running around, and ended up getting killed by them. It's difficult to judge them as foes, usually people either completely hate them all the time or use them to their advantage whenever possible. Usually I gave people fair warning when the balance shifted if they weren't used to being attacked by me as Iltch.
In short it really depends on leadership. I'd recommend playing a Nexun and not doing anything shady, being fairly consistent and just taking over the cabal yourself and setting things how you want them.
-Considering trying this cabal, yet I know next to nothing about it--except from the days before they went defunct. If you have the knowledge to make a comparison between then and now, that'd also be nice.
The only real difference between then and now is the cabal philosophy is far more open ended, there aren't any 4 pillars and complex theories, and the basic cabal philosophy is written out plainly in the cabal. It's easier to get into now then it was then, and easier to play out. The balance doesn't shift as fast as it used to, and different factors go in to what makes things shift.