I don't know anything about the Mitsubishi. The Leaf definitely has a capacity advantage (at the cost of weight), and is approximately the same chemistry. The Volt's thermal and electrical controls are vastly superior to the Leaf.
how do the electric + thermal controls translate to user benefits? More range or more torque? <-- might be a really basic question
They definitely contribute to range and torque, but the most important contribution is to the overall lifetime of the battery. Batteries treated nicely are apt to last much longer. Thermal management is probably THE most important factor in a battery's lifetime.
Ah, that makes sense. Thank you for taking the time to answer my questions :)