Bloodthirsty as of 6.1.1 provides up to 350 additional Weapon and Spell Damage based on the enemy's missing health, scaling linearly starting from 90 percent health remaining.
ZOS noted that this value (Bloodthirsty) is not affected by percentage modifiers.
Infused was untouched in Stonethorn as of 6.1.1, providing 104 additional Weapon or Spell Damage based on the glyph being used.
This value (Infused) is affected by percentage modifiers, so we need to take that into consideration. The video goes over the math, but in general, Infused loses to Bloodthirsty for magicka DPS and is about even to Bloodthirsty for stamina DPS on average.
The calculations can get tricky because Bloodthirsty's overall effectiveness is dependent on a few factors, including how long you are at each health threshold and the existence of executes.
Generally speaking, if you have a powerful execute, Bloodthirsty may be more beneficial since your execute damage will be amped more by Bloodthirsty than by Infused.
In addition, the less time you spend at lower health thresholds, the weaker Bloodthirsty is on average.
Asiangod's personal recommendation would be to stick with 3x Bloodthirsty for all DPS specs, with the exception of Stamina Templars and Stamina Sorcerers. Stamina Templars and Stamina Sorcerers may be better served by running 3x Infused instead.
Watch the video below for the mathematics behind this.