Yeah around 2.5x faster in Java code execution but unfortunately they do not come by default.
https://www.codeaurora.org/cgit/quic/la/platform/art/ ART
https://www.codeaurora.org/cgit/quic/la/platform/bionic/ Bionic
https://www.codeaurora.org/cgit/quic/la/device/generic/art/ Not sure but...
I tryed your build,its working OK,smoother than AOSP especially after I added ART libraries from Ivan's AOSP.I/O performance is OK,it could be a lot better like in some AOSP build I think there is some code you could fetch from CodeAurora to improve it although I havent checked it.