Not may be - definitely is.
From
Listed as Not Working.
From the developer of Xposed himself:
From personal experience - it will never enable if Xposed is installed, and if you try to install it in a dirty flash over an ART - enabled ROM, the ROM breaks hardcore.
Trust me - I tried it numerous ways on my TF700 running a CM-11-derived ROM called cROMBi-kk....
But what ART brought to the table in terms of sheer speed more than made up for the lack of Xposed....