To the people complaining about Isaac items, if it is a passive item it tells you exactly what it does for almost every passive item. It it's a usable item pick it up, read the description, and use it on a room of enemies or a boss and pay attention to what it does. That's what it's all about.
Rebirth gives 100 times more useful descriptions for items than Isaac did. It would be laziness if the intention was for the game was to tell you what every item does, but that was never Ed's intention at all. There's supposed to be mystery to it because if you could see what every item did then you skip stuff doesn't do what you want it to.
But, like I said before Isaac is not for everyone.
Edit: If you really want to spoil it all for yourself use platinumgod.co.uk/rebirth