Just keep your contrast at 70/75 max and same for brightness, and you should be fine (sharpness should be around 20 max, but 10/15 recommended). Don't get obsessed with it, watch anything you like (logo, bars or anything) just make sure you don't only watch content with bars or logos (if logos are transparent, they're fine).
You need to fill the screen completely from time to time, to wash away the IR and use the pixels evenly. I saw very little IR since i have my PA6500, and usually disappears in a matter of seconds, it's not an issue anymore, really.
You just need to adopt the correct behavior and reflexes. Using the wash tool from time to time helps a lot, and of course the pixel orbiter when you have a logo.
With this in mind burn-in shouldn't be an issue anymore.
It's just a different behavior to adopt, plasmas have a wonderful image but need a little bit more care. It's worth it in my opinion.
As for the energy saving, depends on preferences and if you're really concerned into making small savings. Not really important.