User blog comment:YourPrivateNightmare/The mystery of Blue Ezreal/@comment-5761259-20130613184624

Blue build Ez provides a massive amount of utility, while still doing quite good damage. Since the recent patch in which they reduced the damage on elder lizard though, I don't think it is as viable of a pick up. I would much rather get a Blood thirster now, though not blue. To make up for the lost cooldown, I would look to runes or masteries.

As for Muramana, the reason it is so good is that all but his w, which is useless, and his ulti are single target, making the procs go off quite often. With the other mana item, you get quite a bit of damage going, which is essential considering the fact that he really doesn't have any hard core damage items in the build.