PS Audio UO vs P300 or P500

I'm wondering for an improvement in sound quality is it worth purchasing a PS Audio P300 or P500 Power Plant when I already have two Ultimate Outlet's? The UO's work very well though they definitely work best when you don't mix digital and analog into the same UO and when there's nothing but the amplifier plugged into the other UO? Thanks
i have both a p300 and 2 ultimate outlets.

last night i was using one ultimate outlet for a cd player, a juice bar and was not using the p300.

when i connected the juice bar to the p300 instead of plugging directly into the wall, i nnoticed an audible softening of the sound.
If you're going to move from what you currently have to a power regenertion unit there are better components out there than PS Audio. Try looking into a used Exact Power unit or one of the APS units. Otherwise I think the UO is one of the best products PS Audio offers.
regarding the exact power unit, i read a review in the inner ear and one comment caught my attention.

the reviewer noticed a brightening of the sound when the exact power unit was in the stereo system.