Yesterday I played Swain. I thought buying Zhonya's hourglass is pretty awesome on him, because of ap and armor of course, but mainly because I like to focus on the active. A pretty cool thing about it is, that when you use Zhonya's while he has his ultimate on, it stays active, which saved me very often. I was able to use Zhonya's at low health and when my Zhonya's active expired in the teamfight, I had like half hp or so.
The thing I wish to know from you guys is that which champs are good with Zhonya's and which are not, because I don't know which ultimates get interrupted by Zhonya's and which not.