User blog comment:Heroduderox/Theoretical Braum Comp/@comment-24165677-20140426165405/@comment-5331854-20140428110732

Both have their pros and cons.

Lucian can double-AA, which applies two stacks of Braum's innate (only basic attacks count) within a half-second, giving him an early edge compared to Ez (which is important because Braum's innate is usually more potent in mid- and endgame when teamfights occur and the ADC has some AS going). He can also stick to a target thanks to his W-de/buff and his slow-removing dash, but also disengage with his ult. An additional bonus is that his abilities won't get minionblocked as hard as with Ezreal.

Ezreal has a higher poke potential due to Q's CD-reducing nature and generally has more AS when he can keep up his assault, which is nice for Braum's innate. He can also buff Braum's AS with the W, which is only a small bonus, but still a bonus. He is crippled by a slow, though, so he can't chase efficiently even with his blink (he has his ult to compensate for it, though). Also, he's a bit lower on the Base MS-department.

Ezreal and Lucian are roughly equal in their farming- and pushing-potential when given a classic ADC-build.