The Ender Tank is a multiblock structure, and can store a lot of fluid in one place (64 buckets per internal block, by default). It requires power to perform operations - if you can't afford to extract stuff, it will simply taunt you.
Similar to the Charge Pads, there are three tiers of Health Pad: Redstone, Resonant and Creative. They will gradually heal you, half a heart at a time, with each tier having a different regen rate. The energy cost is configurable.
The Exchanger will affect blocks in a given radius, one radius at a time (like a shockwave), when you right click.
You'll get a visual representation of what blocks the Exchanger will affect.
Charge Pads work in any orientation, and charge things in your inventory, and items on the ground, from up to two blocks away. This means you can hide it behind a block, but there's a loss of up to 50% if you're more than ~0.5 blocks away.
Includes the Ender Tank and all tiers of both the Exchanger and Charge Pad. Not included: Health Pads.