I've done a lot of PBO testing, with all Agesa versions on my 3900X.
I arrived at the conclusion that, on my system at least, PBO is not worth the heat and power consumption it generates vs the performance gain over stock operation. I can dial a CCX overclock which is better than PBO in almost all areas: Multicore performance gains, heat and power consumption. For no AVX workloads, you even can match the slight single core performance you lose by going all core or ccx overclock, and gaining a good multicore performance in the process.
Best all sustained core clocks I've seen on my cpu with PBO in AVX situations is 4.15Ghz, and it depends a lot on temperatures, so it is not constant. By contrast, you can set an all core of 4.25Ghz with less generated heat at lower than PBO voltages, with no variance due to temperature fluctuations.
The algorithm commanding PBO is very temperature dependant. To get increased clocks over stock operation, PBO increases voltage, which in turn increases temps and power. The increased temps lower the clocks, and the cycle begins again. It's a chiken or egg situation mostly. With a manual OC all of this is not happening, you only care about your cooling solution.
PBO would be good for those people who want a little more performance than stock, with minimum user effort, and forget about stability testing a manually overclocked system. This user friendly feature comes at the cost of heat/power consumption vs. performance gained over stock tough.
Since you can set a ccx or all core overclock in desktop with Ryzen Master without reboot needed, I think the best way to get increased performance on Zen2 is not to use PBO at all, just leave the cpu at stock values on BIOS, and set your desired overclock on Ryzen Master when you need or want more performance.