Many users experience completion problems. It's unfortunate for a product that claims to be the #1 PHP programmer tool. Sure, there are a lot of good things in ZDE 7, but many are thanks to Eclipse on which it is based. I've been using ZDE on Windows XP, Windows 7, SuSE Linux, and Ubuntu Linux -- in some environments it works, in others it doesn't.
My opinion is that the last *really* good version of ZDE was the 5.x series -- these days it feels a lot more like bloatware; and I can get most things I need from Eclipse or other "development environments".
I don't mind paying for good, rock-solid products; unfortunately ZDE 7 isn't one of them.