ART has better performance and better battery life on paper at least. Should I consider switching to it on my moto g? What are the results I can expect? What precautions should I take? Is it easy to turn back to dalvik?
Just try it by yourself. I've felt no real difference. Maybe it is something that is device specific or there is just a very small difference.
But it can change with Android 5.0 'L' because ART on Android 4.4 is some sort of beta version.
Switching to ART is as easy as switching back to Dalvik.
Settings > Developer Options > Select Runtime.
There you can choose
You have to reboot your phone to apply the changes.
If you want to go back to Dalvik, redo the steps and select
It's worth noting that rebooting after switching runtimes may take several hours - at least this has been my experience. This is because the ART recompiles all your applications. It may even do it more than once if the process is interupted (e.g. due to battery drain) - i.e it start over again at the top.
I'm hoping that switching back will be quicker since hopefully the compile step (unecessary for the Dalvik JIT) is what has slowed it down. I have not yet switched a device back to Dalvik so I'm not sure if this is correct or not.