it used to be worth while, the imperial city dlc nerfed it into the ground.
Yeah, I switched to dark deal. It's pretty nice in duels, lets you storm run forever, and high magicka regeneration almost ensures face tanking at its best. Dark exchange just felt like a dps drain.
I just got the ability dark exchange, and I started using it, and the amount it heals is honestly AWFUL, does it get better later in the game or what, because I can just summon a clannfear, dismiss it and repeat 3 times to have all my health back, with dark exchange I have to do it 15 times......