His cooldowns are big, so his burst healing really suffers between Bio Kill Switch CDs, but his sustained healing more than makes up for it. He's not very good for burst comps, but he's plain OP for poke comps with good disengage (and he can disengage himself as well). You can reduce BKS CD with one of the talents, but then you need to hit only 1 enemy with W, which isn't the easiest thing to pull off.