I can only really comment regarding WvW, because that’s where my focus lies. I’ve tossed this question around in my head so many times. I believe going completely dire or rabid is a wrong move. I collect enough toughness and precision from the rabid (1500ish toughness/ 25-35crit chance) and then start equiping Dire.
In theory, I want enough toughness to survive a thief/ mesmer blitz and enough vitality to make me more hearty against condition focused enemies.
Also, my current spec is heavily focused on conditions so after I reach my toughness/precision goal I start stacking the dire because it gives me that boost in power which is nice without sacrificing any condition stacking while doing so.