Dark regeneration is pretty much the only valid choice for pvp. 90% of the cases used in combination with a glyphed healthstone which is after BF is slightly less than a 70% heal over 12sec on a 2min cooldown.
Should a 30% mortal coil be used with it, it's about 95% total healing you do, about the same as dark regeneration + healthstone pre-battle fatigue.
Battle fatigue has fucked up a lot of our self healing, yet the healthcosts of our spells are still the same. That's the reason why we are getting a glyph for ember tap and drain life as well.