Without ACD, cloaking is purely defensive as ships that are cloaked can't attack. No worries.
And this is what needs to be remembered. For some reason, I think we are all forgetting how, despite our minds telling us otherwise (Thank you ACD Phantoms for messing with a number of us), that cloaking is NOT an every turn action. It's actually a very situational (though effective) action.
At first, I thought this upgrade was a total toss away. But then I read over it again.
And then again.
And then I read the posts in this thread. And I've decided.... it's a worthwhile upgrade.
While the toss away factor blows, ideally, you don't WANT to use this more then once or twice a game as is because you wont be getting shots when you do. Chances are you get 2 or 3 cloaks in before it drops on ya, and those extra evade dice are guaranteed for at least 1 round even if you do roll the eye (sidenote: Think this has to be run with stygium to be effective). And when you do use it- TADA!- You have a much better chance to get out clean in a rough positioning round, and as a bonus, you get to reposition nicely for next turn, whether before or after dials are set!
The die roll makes it wonderfully scum. It doesn't ruin it by any means.