For those of you who do not know ART, please refer to this post (credits to OP)
Since we already have Kitkat and Android L is just around the corner, why don't we discuss ART and its impact on the performance of our phone?
I know this feature is HIGHLY experimental, but given that Kitkat is on its 4th update (4.4.4) already, I'm assuming that at least it will be more stable.
For me, i think the overall time for apps to open slightly became quicker that before and so far no problems on compatibility on apps. Xposed is still working.
Can't wait for L