Yes, the effects you mentioned, I find it difficult to evaluate their real impact and decide if this is a better item than another, more simple one.
And there are also those who only take effect after a certain condition, like a critical hit for instance. Is it worthwhile to equip this ? Most items seem to have conditions like that attached, and I find it difficult to compare these against one another and decide which one is best to keep on me.
The ones with the magical conditions work best in sets. For some of the magical effects you'll need stacks of five until something happens, so if you can get those stacks in one or two turns, that's great. If you need the whole battle to build them, it's probably not worth it. The tooltips tell you how much you need.
For crits, attack rolls (both physical and spell attacks) can land crits. If you have a character that can make multiple attacks in one turn, say a fighter, they are more likely to crit than say a wizard who has only one action per turn unaided and might not even always use attack spells. So the crit stuff is probably more helpful for the fighter.
