Educational video on harmonic dampers/balancers

Pretty interesting information on how dampers work.

I'm getting close to the time I need to get a harmonic damper and been doing some reading into the fluidampers and rattlers.

I don't know how much energy the viscous fluid dampers eat up compared to the rattlers. I got the impression that the rattlers can return energy to the system, whereas the viscous fluid dampers dissipate it as heat. Is anyone able to either confirm or refute that?

Even if the viscous fluid dampers consume some energy compared to the rattler style, I get the impression that it's a little better for long term life of the engine. I'd love to hear your guys' thoughts and experiences on the matter. I'm going to talk to some of the engineers at work on this over the next few weeks.