For serious PVE I prefer Fireborn. If I am over leveled I would swap it to Song of flame, because its unlikely I will die at some point anyway. I prefer high DIS, moderate INT (90% of the time I am going to be sitting at max super anyway, why make it more?), low STR. I usually self res on any death, as almost always I will have my super back before dying again. If you are in an area where death matters, go with fireborn. It honestly is the highlight of not only the sub-class, but the warlock currently. In PVP I usually use radiant skin instead of fireborn. The self res animation takes a while and you can easily get shot down without the extra damage reduction.