I have an old 1950's house with dubious modern wiring. I have tremendous issues with noise in my system, particularly with tube amps (which I love, love, love the sound of tubes). I hate noise from the system drives me bonkers. The P5 was the first thing that really, really dialed the noise down. A big part of it is I consistently get 125v from the wall and that (along with the 4% THD riding on the line) did a number on the power transformers of a lot of tube amps I've had go through my system.
Re: load. I have a Type 45 SET amp, a pair of 375 watt subwoofer amps, my massively oversized tube preamp, my Blu Ray player, my Auralic Vega DAC, my Roku streaming device, AND my 4k Epson HT projector plugged into it. With the projector off, I never go above 35% capacity for the unit. With the projector on, it's about 60%. Plenty.
Re: Dynamics - if anything, this unit increased dynamics by lowering the noise floor, which means you hear more details and more magic at low levels, which (all by itself) increases your dynamic range. Remember, dynamic range is not just how much louder your system will get before compressing or overloading your room. It's also how much quieter can it get before disappearing into the noise floor.
Video: The most shocking thing of all was the increase in video quality. I'm just as hard-core a videophile as I am an audiophile and the amount that the P5 improved my picture quality is rather stunning. Black levels and color saturation went from excellent to spectacular.