I have a Powerlab 6 and absolutely love it. Buying it and a parallel charge board was one of the best RC decisions I have made. Also, I do know some high power Heli guys that are always looking for a more powerful charging setup. They already are using your dual PL8. But that is not me.
For me, even the powerlab 6 is overkill. I am a fixed wing guy and the largest batteries I currently use are 4S-4000. I probably max out at around 300 watts of charging power. (4 4S 4000s in parallel charging at 1C) Also, right now I find myself using my parkflyer sized planes the most. These are in the 1500-2600 3S battery size.
So... If I'd be in the market for a new charger, I guess I'd be looking for a full feature 4S 500 Watt minimum system. I am willing to spend some more for a more accurate, higher quality, and safer charger. Parallel charging for me is easier than multiple charges. I am not sold on needing the bump system. It's easy enough for me to set the charge rate myself.
My only quibble with my PL-6 is the display. I'd prefer a larger screen with more status information on each screen. But it's really a rather minor concern.
This is just my thoughts and where I am today...